More Popular Spinoff

Sometimes, a Spin Off series ends up becoming more popular than the original that spun it off. See also Adaptation Displacement, where the vast majority of fans are unaware that it started in another medium, and Sequel Displacement. Also see Breakup Breakout.

Anime & Manga

 * Akagi (Ten)
 * Magical Girl Lyrical Nanoha (Triangle Heart 3 Sweet Songs Forever)
 * Sailor Moon (Codename Sailor V)
 * Gundam Wing (Mobile Suit Gundam) - More popular in America, but not Japan. Probably because it was the first Gundam series to get a decent American air-slot, not to mention airing in North America before the original 1970s series.
 * Dirty Pair (Crusher Joe) - Also more popular in America and Europe, but not Japan.
 * Paradise Kiss (Gokinjo Monogatari) - The former is more popular outside of Japan since, unlike it, the latter does not have as many official foreign language translations. (Gokinjo Monogatari has French and Spanish translations for the manga and an Italian translation for the anime, at least, but Paradise Kiss has at least 10 translations, including to English, according to That Other Wiki.)
 * X 1999 (Tokyo Babylon)
 * Outlaw Star is combination of both Adaptation Displacement and More Popular Spinoff, as most people only remember the anime, which was adapted from the manga, which itself was a spin-off of a manga called Future-Retro Hero Story.
 * Great Teacher Onizuka to Shonan Junai Gumi.
 * The anime adaptation of To Aru Kagaku no Railgun was originally presented as a spin-off of the anime adaptation of To Aru Majutsu no Index, but wound up being more popular and selling more DVDs than the Index anime.
 * Excel Saga (Municipal Force Daitenzin)

Comicbooks

 * Spider-Man (Amazing Fantasy)
 * Many Marvel characters of The Sixties started off in anthology series. The Mighty Thor and Doctor Strange are other examples. The difference here is that Spidey's intro was in the final issue of Amazing Fantasy, while the other anthology books starring future Marvel megastars continued with their anthology titles and formats for a period of time.
 * Batman began as just one of many characters rotating through the spotlight in Detective Comics.
 * Superman was originally just the central story in Action Comics #1. And while he was featured on the cover, Superman didn't get another cover until Action Comics #7, and wasn't regularly featured on the cover until #16 or #19, depending on interpretation. Action Comics is still alive today... as a Superman title.
 * Donald Duck started out as one of six characters, all barnyard animals, in a Disney comic strip in the early '30s.
 * Marvel Comics' Wolverine first appeared as antagonist for the Incredible Hulk, and has gone on to eclipse him in some respects.
 * ABC Warriors spun out from Ro-Busters, and managed to last much longer and attain greater popularity.
 * Popeye began as a minor character in a comic strip called Thimble Theatre.
 * The Smurfs actually first appeared in, back before they became popular, Peyo's major series Johan and Pewitt (Johan et Pirlouit). Guess which series fell in the shadows after the blue critters showed up, to the frustration of Peyo?

Films

 * White Christmas is only arguably a spinoff of Holiday Inn (both movies feature Bing Crosby, the song "White Christmas" and other songs by Irving Berlin, and a Hey Let's Put On a Show plot), but it's certainly the more popular movie.
 * Pirates of the Caribbean was based on the Disney Theme Parks attractions of the same name; its popularity led to Jack Sparrow, Barbossa and Davy Jones being added to the ride.
 * Pink Panther
 * Remember all these kids for whom Pink Panther is a cartoon series... or now an insulation mascot.
 * On Spain, the Pink Panther is more associated with a pink sweet bun children love eating than with any of the movies. At least the eponymous pink panthes appears on the package.

Game Shows

 * The Price Is Right started as a more relaxed game of price guessing hosted by Bill Cullen in the late 1950's. However, when Mark Goodson decided to produce a revival in the 70's, he decided to re-work the show into a carnival of glitz with elements he scraped from the popular Let's Make a Deal (i.e. plucking contestants from the audience to play mini-games, three giant doors, etc). The revised version, dubbed "The New Price Is Right", eventually eclipsed the original in popularity, and still airs to this very day. Most viewers barely even realize that their favorite show has been around much longer than they thought.
 * Family Feud was a spinoff of the Audience Match portion of Match Game. It eventually overtook Match Game in the ratings, and even took Match Game panelist Richard Dawson with it.

Literature

 * The Adventures of Huckleberry Finn is considered, at the very least, a more important work than Tom Sawyer.
 * Captain Leopold was originally a minor character in a story about series character Al Darlan. Hoch went on to write over a hundred stories about Leopold.
 * Beverly Cleary's first book was about an ordinary boy named Henry Huggins. One of the supporting characters was his friend's pesky little sister, Ramona Quimby. She eventually got her own book series which is more popular than Henry's.
 * Lord of the Rings to The Hobbit.
 * And both to Tolkien's Magnum Opus, The Silmarillion.

Live-Action TV

 * Mister Dressup (Butternut Square)
 * The Andy Griffith Show (The Danny Thomas Show)
 * Xena: Warrior Princess (Hercules: The Legendary Journeys)
 * Whatever Happened To The Likely Lads? (The Likely Lads) - well, more a sequel than a spinoff, but kind of a different series anyway.
 * Happy Days (Love American Style)
 * Extreme Makeover Home Edition (Extreme Makeover)
 * Family Matters (Perfect Strangers) - to the point that Perfect Strangers isn't seen on national TV anymore.
 * At times Angel received higher ratings than Buffy the Vampire Slayer.
 * Buffy in turn was far more popular than the film from which it originated.
 * Good Times (Maude)
 * Star Trek the Next Generation had to work hard to get out of its predecessor's shadow. The first series of TNG was lukewarm at best (and garbage at worst), sneered at by more purist fans, and yet by the second or third season it was well and truly its own show and went on to be the longest running out of all Star Trek Spin-offs (beating Deep Space Nine by only two episodes). Whether it's actually more popular is all up for debate.
 * Stargate SG-1 (Stargate)
 * NCIS was originally a spinoff of JAG, but has gotten consistently better ratings and reviews since its debut.
 * The Honeymooners was originally a segment in The Jackie Gleason Show.
 * Diagnosis Murder (Jake And The Fatman)
 * Law & Order:Special Victims Unit has received more acclaim and ratings than the original Law and Order and has run nearly twice as long as Homicide Life On the Street.
 * Benson lasted for three seasons longer than Soap, its parent show.
 * Cheers and its spinoff Frasier are both very popular and both lasted a whopping 11 seasons, although Cheers has 11 more episodes.
 * CSI: Miami, at least internationally.

Music

 * You ever hear of the band Rainbow (no, not the Ritchie Blackmore band)? No? Wicked Lester? No? What about Kiss? Yeah, Gene and Paul founded Rainbow which became Wicked Lester and then, under the names Gene Simmons (his name during the Wicked Lester times was Gene Kline and his real name is Chaim Witz) and Paul Stanley (real name Stanley Eisen) they founded KISS. Both Peter Criss (also not his real name) and Ace Frehley (also not his real first name) were in Wicked Lester and others had been as well.
 * Journey started out as a vehicle for guitarist Neal Schon and keyboardist Gregg Rolie after they left Santana (who were still extremely successful). They've since sold 75 million records worldwide.
 * Semisonic began as an informal side project for Dan Wilson and John Munson of the cult band Trip Shakespeare. Hugely popular in their hometown of Minneapolis, Trip Shakespeare couldn't translate that success to the rest of country and eventually broke up. Wilson and Munson focused their attention on Semisonic, and had a huge hit several years later with "Closing Time".
 * Michael Jackson (post-Jackson 5).
 * Goth pioneers Bauhaus are considered an extremely influential band, but their members all had more success (in America anyway) with their post-breakup work: Peter Murphy as a solo artist; Daniel Ash, David J and Kevin Haskins in Love & Rockets.
 * Justin Timberlake post-'N Sync.
 * JT's solo albums have only sold a fourth of what *NSYNC sold, but he has had more number one hits and far more critical acclaim than *NSYNC ever did.
 * Beyonce (post-Destiny's Child).
 * Dr. Dre and Ice Cube from N.W.A.
 * In turn, Eminem over Dr. Dre.
 * Crosby, Stills and Nash ended up outlasting and outselling the bands they left (The Byrds, Buffalo Springfield and The Hollies).
 * Motorhead (Hawkwind)
 * Slipknot was originally a side project of Stone Sour vocalist Corey Taylor. Many Slipknot fans don't even know who Stone Sour is, much to the frustration of Stone Sour fans that dislike Slipknot.
 * The Polyphonic Spree was formed by a few members of cult post-grunge band Tripping Daisy after the death of guitarist Wes Berggren and are much more well known than their parent band. One of the few members of Tripping Daisy that didn't join the Polyphonic Spree was Ben Curtis who later formed the Secret Machines with his brother (and later left to form indie band School of Seven Bells)
 * Scottish indie band The Yummy Fur, while adored by their small cult audience, were virtually unknown during their 1990's heydey. Lead singer/only constant member John McKeown found more success with his next band, 1990s.
 * Paul Thomson and Alex Karpanos (then going under Alex Huntley), two former members of The Yummy Fur, formed Franz Ferdinand a few years after they left the Revolving Door lineup of the Yummy Fur.
 * Death Cab for Cutie originally began as a solo project of Ben Gibbard, the guitarist for the now obscure band Pinwheel.
 * Similarly, Porcupine Tree started as a solo project for Steven Wilson alongside his main band No-Man; as Porcupine Tree became a proper band following Up The Downstair and grew in popularity, No-Man became the side-project. No-Man is still alive at the time of writing, but it's less of a priority for Steven Wilson because Porcupine Tree is much more popular nowadays.
 * Another case of "beloved cult band begets more popular group" is The Hold Steady, formed by two former members of Lifter Puller.
 * Uncle Tupelo were famous for being the Trope Codifier of alternative country, but when the band broke up the band's two leaders and various other members formed two different bands. Whereas Jay Farrar's band Son Volt is arguably only barely more famous than Uncle Tupelo, Jeff Tweedy's band Wilco is perhaps one of the most critically acclaimed alternative bands of the past 20 years.
 * Similarly Joy Division only released two albums before their singer also committed suicide, but the ensuing post-Ian Curtis band, New Order, is equal to them in terms of popularity and influence. Not in sales though, New Order is far ahead of Joy Division there.
 * Pearl Jam formed from two bands: Mother Love Bone (who were on the cusp of stardom when their singer Andy Wood died of a drug overdose) and Temple of the Dog (formed by former MLB members Jeff Ament and Stone Gossard as a brief side-project also involving members of Soundgarden and then-unknown singer Eddie Vedder as a tribute to Wood before starting their next project). After Pearl Jam became famous, Temple of the Dog and Mother Love Bone's albums (they only had one apiece) became big sellers due to the Pearl Jam connection (and in the case of Temple of the Dog, also because of the Soundgarden connection)
 * Bjork was the lead singer of The Sugarcubes, an Alternative Rock band that was one of the first Icelandic artists to ever find any mainstream recognition outside of Iceland. Whereas the Sugarcubes are fondly remembered by fans of 80's alternative music, Bjork's popularity completely eclipsed theirs by the time she released her solo debut album.
 * And before that, she was the singer of the post-punk/goth outfit KUKL.
 * And before THAT she was the singer of the punk band Tappi Tíkarrass.
 * The Yardbirds have three popular spinoffs.
 * Eric Clapton went on to play in the psychedelic rock band Cream and is probably even more popular as a solo artist.
 * Jeff Beck who replaced Clapton as the lead guitarist has also had a very lucrative solo career.
 * Jimmy Page replaced Jeff Beck, all of the group but Page left the band. Page recruited new band members and toured under the name The New Yardbirds for a while before changing their name to Led Zeppelin. Led Zeppelin became one of the most popular rock bands of all time.
 * Similar to the above, John Mayall and the Bluesbreakers was a Revolving Door Band whose former membership includes not only Eric Clapton (after he left The Yardbirds and before he started Cream), but also Peter Green, Mick Fleetwood, and John McVie.
 * Electric Light Orchestra from The Move. ELO was originally just going to be a side project for The Move, but lead singer Roy Wood left the organization after the first ELO album, so the others just continued on as ELO.
 * Savatage was a Progressive Metal band that ran from 1978 to 2001, known in particular for their Rock Operas. One such album, Dead Winter Dead, featured a song that became a surprise hit: "Christmas Eve / Sarajevo 12/24". Decided to experiment further with the style, they became founding members of Trans-Siberian Orchestra. TSO has became extremely successful for their Christmas themed rock operas, while Savatage is almost forgotten and disbanded to focus on TSO and other projects.
 * Most people consider Days of Future Passed to be the first Moody Blues album; it was indeed the first of their Justin Hayward era, but their Denny Laine era produced one earlier album, The Magnificent Moodies. This means that Seventh Sojourn, which even they regard as their seventh album, was actually their eighth.
 * The early 90's French indie band Darlin' contained Thomas Bangalter, Guy-Manuel De Homem-Christo and Laurent Brancowitz. Darlin' didn't last very long, but Bangalter and De Homem-Christo eventually began recording as Daft Punk (named after a dismissive comment in a review of an early Darlin' show) and Brancowitz became a member of the popular indie band Phoenix.
 * Young musician Sonny Moore was a vocalist in a post-hardcore band From First to Last, with modest success and a record deal. After going through some trouble with his vocal chords and preparing to do a solo album, he started experimenting with electronic music that he liked as a kid, releasing instrumental dubstep under the name of Skrillex.

Radio

 * A Prairie Home Companion, from Garrison Keillor's weekday morning public radio show in Minnesota, which he stopped doing in 1982.
 * The Dr. Demento Show started out in 1970 as a recurring guest segment on the weekly show of another DJ named Steven Segal ("The Obscene Steven Clean"). In 1971 Dr. Demento got his own timeslot for a few months, only to be fired along with the rest of the station's on-air staff. Then after guesting again on Segal's show on a different station, Dr. Demento permanently spun off into his own show in early 1972.

Tabletop Games

 * Warhammer 40000 is much better known than Warhammer Fantasy. Just look at how many examples on this very wiki describe elements common to both as coming from 40K!

Theatre

 * The Richard Strauss opera Ariadne auf Naxos was originally written a Show Within a Show in a production of Moliere's Le bourgeois gentilhomme for which Strauss also composed substantial incidental music.

Videogames

 * Wolfenstein 3D v.s. Castle Wolfenstein (an overhead stealth action game) is one of the earliest and biggest examples in the medium.
 * Unreal Tournament, a multiplayer-centric offshoot to Unreal, which was more singleplayer-centered.
 * The Legend of Zelda Ocarina of Time got some of this treatment upon its initial release, leading to some newer players to call its sequel "The Legend of Zelda 2: Majora's Mask''.
 * Starsiege, sequel to the Earthsiege series of Humongous Mecha Simulation Games, has been all but displaced by Starsiege Tribes and its sequels, multiplayer FPSs with an emphasis on team play, jetpacks, and no HERCs in sight whatsoever.
 * beatmania IIDX (Beatmania). In fact, the original 5-key series is now retired, while IIDX continues to get sequels.
 * Super Mario Bros. (Donkey Kong and Mario Bros.)
 * And Wario Land from Super Mario Land, with Wario Land receiving its own in the form of Wario Ware.
 * The King of Fighters (Fatal Fury and Art of Fighting).
 * While Psycho Soldier and Ikari Warriors don't exactly count, as those weren't fighting games, the characters ported to King of Fighters (Ralf Jones, Clark Still, Athena Asamiya, and Sie Kensou) are much more well known for their roles there than in their debut games. Also, K Dash's partner, Maxima, was originally the main character of Robo-Army, a Neo-Geo beat-em-up during the platform's early years.
 * Many World of Warcraft players are unaware that the War Craft series also has three Real Time Strategy games, two of which were best-sellers. A sort of a running gag among the fandom is somebody mentioning having played Warcraft III and a WoW player responding something along the lines of: "World of Warcraft 3? I didn't know there was even one sequel."
 * This lead to a rather hilarious April Fools joke by the staff, announcing a new game that was a RTS-style spinoff of World of Warcraft. They then went on to describe Warcraft III, as if it were an up and coming new game set in the World of Warcraft universe.
 * Prince of Persia: The Sands Of Time and the two following sequels, compared to the original series that was quite popular in its own day. The Sands of Time trilogy was the first successful attempt to take the Prince into 3D after the failure of 1999's Prince of Persia 3D.
 * Persona, specifically Persona 3 (Shin Megami Tensei). Especially in America, where a steady flow of Mega Ten games is a recent occurence, while in Japan, the franchise is considered one of the Big 3 with Dragon Quest and Final Fantasy. Even in Japan, the extreme success of the recent Persona games is rapidly eclipsing the other Mega Ten games it spawned from.
 * Rune Factory from the Harvest Moon series, but mainly in Japan. RF 1 was produced as a Harvest Moon spinoff, but sold so much better than most HM games that subsequent games were spun off into their own series. They still keep the Harvest Moon label in the West, just as Persona games still keep the Shin Megami Tensei label.
 * Many fans of the DJMAX series seem to be unaware that there was a PC DJMAX game that preceded DJMAX Portable, or at least have only heard of it.
 * Lately, DJMAX Technika has been gaining popularity, becoming even more popular than Portable in areas that have Technika arcade machines.
 * Goldeneye was a successful movie, but largely considered average in the James Bond series. GoldenEye 007 for the Nintendo 64 is one of the most beloved games of all time and a triumphant aversion of The Problem With Licensed Games.
 * Heroes of Might and Magic, a Turn Based Strategy series, has all but displaced Might and Magic, the original first-person, party-based Role Playing Game series.
 * Modern Warfare, a contemporary FPS compared to Call of Duty's World War II setting.
 * Battlefield's modern-day installments (2, the Bad Company series, and 3) are similar to this, overshadowing the original Battlefield 1942 and the less-than-well-received Vietnam and 2142.
 * The Puyo Puyo games was a spinoff of Compile's kiddie RPG series Madou Monogatari, repackaging the slime-type enemies into Falling Blocks.
 * Guilty Gear X and all of its sequels. Sort of justified in that it wasn't until Guilty Gear 2: Overture that the X series was confirmed to be a spinoff.
 * NANACA†CRASH!! is a fairly popular browser game that requires no translation to understand. CROSS†CHANNEL, the original Porn With Plot Visual Novel that inspired it, did not receive a Fan Translation until August 2009, and remains relatively obscure.
 * Da Capo is semi popular Visual Novel series that started as a bonus scenario in Suika, which remains rather obscure.
 * River City Ransom and Super Dodge Ball to Renegade, which were all part of the Kunio-kun series in Japan, but are hardly related to each other outside of having the same main character. Even in Japan, the more comical Downtown Nekketsu sub-series of Kunio games had a bigger following than the original "serious" Nekketsu Kōha games.
 * The Warlords Battlecry series is a real-time spin-off of the turn-based Warlords series.
 * Portal to Half-Life. Portal, which takes place in the Half-Life universe, was launched as part of a bundle pack whose main attraction was the long awaited Half-Life 2: Episode 2 and Team Fortress 2. Many reviews indicated that Portal stole the spotlight. The blockbuster sales and positive critical reception of Portal 2 have cemented its status.
 * The Guardian Legend was a Surprisingly Improved Sequel Gaiden Game to the experimental MSX shmup Guardic, which had nonlinearity going for it but little else.
 * The flash game Bloons Tower Defense, a tower defense-styled game, was actually a spinoff of the game Bloons. Bloons TD became so much more popular that there is now premium content in it.
 * Monster World to Wonder Boy, which specifically spun-off from the second Wonder Boy arcade game Monster Land (Monster World was the title of the Sega Mark III version in Japan). There's a reason why the Compilation Rerelease of the whole series is called the Monster World Collection and not the Wonder Boy Collection.
 * Shining Force (Shining in The Darkness)
 * First-person shooter Duke Nukem 3D is far better known than earlier platformers Duke Nukem I and II
 * Super Robot Wars to the Compati Hero Series
 * Puzzle Bobble (aka Bust-A-Move) to Bubble Bobble
 * Metal Gear Solid, depending if you view it as a spin-off to the MSX2 Metal Gear games instead of a sequel.

Western Animation

 * Betty Boop (Bimbo the Dog)
 * In turn, Popeye from Betty Boop. Not to mention, Popeye started as a newspaper comic that spun out of another comic, an anthology called Thimble Theater.
 * Donald Duck's Classic Disney Shorts to Silly Symphonies.
 * Celebrity Deathmatch (Cartoon Sushi)
 * The Simpsons (The Tracey Ullman Show)
 * Beavis and Butthead and Aeon Flux (Liquid Television)
 * Daria probably wasn't quite as well-known as Beavis and Butthead, but was still quite popular, retains a loyal fanbase and is often seen as defining the 90s.
 * The Smurfs (adapted from a comic which was a spin-off of Johan and Peewit)
 * Aqua Teen Hunger Force to Space Ghost Coast to Coast (which, in turn, was a parody of the original 60's Space Ghost series that would've probably been completely forgotten without its spinoff).
 * Harvey Birdman Attorney At Law to Birdman and the Galaxy Trio.
 * Godzilla the Series (better loved by Godzilla fans disappointed by the American film on which the series is based)
 * The Fairly Odd Parents, My Life As a Teenage Robot, and Chalk Zone originated from Oh Yeah! Cartoons.
 * On Cartoon Network, the following cartoons originated from What A Cartoon!: The Powerpuff Girls, Cow and Chicken (Which eventually spun off the more intelligent I Am Weasel), ~Dexter's Laboratory~, Johnny Bravo and Courage the Cowardly Dog. As compilations intended to produce spin-offs, this was basically the intended result.
 * Adventure Time originated from the short-lived Oh Yeah! revival Random Cartoons. Interestingly enough, Random Cartoons was a Nicktoons production, while Adventure Time currently airs on Cartoon Network.
 * Angela Anaconda from Ka Blam!; mention Ka Blam! in an Angela discussion and no one will know what you're talking about. Oddly, Angela aired on Fox Family (now ABC Family) though Ka Blam! was on Nickelodeon.
 * Spider Man and His Amazing Friends, from a solo Spider-Man cartoon made specifically to get the attention of the major networks. The original has since faded into obscurity, despite actually being a strong show in its own right. (Try putting "1981 Spider-Man" through Google.)
 * The Grim Adventures of Billy and Mandy (from The Grim And Evil Show)
 * My Little Pony Friendship Is Magic (from the 80's My Little Pony cartoon)
 * While Friendship is Magic has a far bigger adult following than the original cartoon ever did, this doesn't change the fact that most people in general undoubtebly still think of the original 80's version rather than Friendship is Magic when the hear the term My Little Pony.
 * My Little Pony (the toyline) to My Pretty Pony
 * Word Girl began as a series of shorts on Maya and Miguel

Webcomics

 * Friendly Hostility (Boy Meets Boy) And the creator is perfectly content if people just forgot the first comic happened all together.
 * Girly, from Cute-Wendy, which was itself a more popular "alternate art style" variation of a comic just called Wendy (which the artist expunged from the internet as punishment for being awful).
 * One could find Mulberry comics much more easily than comics from the series where Mulberry first appeared: Marin Meadow. After the cartoonist's GeoCities website died, he didn't bother moving the Marin Meadow comics to his current website, since he doesn't like how most of them turned out.

Web Originals

 * Nation States (Jennifer Government) The game was intended to only have a few thousand players and last a few months at most. Two million accounts, seven years, and copious amounts of improbable world-building by the players later...
 * The Angry Video Game Nerd was originally just a two-episode thing made for Cinemassacre.com.

Real Life

 * New Zealand? Where is old Zealand anyway?
 * New York, Boston, and Richmond (Virginia) are much more populous and famous than the English cities they're named after.
 * Likewise with New Jersey to the Crown Dependency of Jersey.
 * Portland, Oregon has done the same thing to Portland, Maine.
 * And it came down to a coin toss to determine if we would be Boston, Oregon or Portland, Oregon.
 * Similarly, Calgary in Canada is far more well known than the tiny bay and mansion house on the Ilse of Mull in Scotland that it was named after.
 * Baltimore. (Baltimore.)
 * Actually the city is named for Lord Baltimore, who once controlled the area. His crest still makes up the Maryland flag.
 * Mozilla Firefox (Netscape Communicator/the Mozilla suite/SeaMonkey)
 * Netscape Communicator (NCSA Mosaic)
 * Additionally, Mozilla Thunderbird is to the e-mail client portion of Netscape and the Mozilla suite as Firefox is to the Web browser portion.
 * UNLV (University of Nevada, Las Vegas-founded in 1957) is larger and more famous than the original University of Nevada in Reno (founded in 1874). Although the latter's official name is now "University of Nevada, Reno" they've taken to billing themselves as "Nevada" in athletics and other events to emphasize that they were first (though the state of Nevada recognizes both campuses as flagship schools).
 * The University of Alaska's Anchorage campus has done the same thing to the original campus in Fairbanks.
 * The operating system Ubuntu, which started out as a fork of the older Debian distribution, managed to become one of the most popular Linux distributions, to the point where it has quite a few forks of its own.
 * Likewise Microsoft Windows was originally an add-on program for MS-DOS, eventually merging with the text-based OS and finally replacing the DOS kernel when NT was released to form a stand-alone operating system.
 * Linux itself is a more popular spinoff of UNIX.
 * Wikipedia is extremely popular with numerous articles in multiple languages while its predecessor Nupedia was closed down within a few years of Wikipedia's formation.
 * This site, which spun off from a thread from Buffistas.org.
 * The Scuderia Ferrari was originally Alfa Romeo's racing team in the 1930s before becoming a separate entity. Alfa Romeo still sells way more cars but Ferrari is more glamorous and has won far more Formula One races than Alfa Romeo.