B-Side

Often when bands release a single, they want to put a little extra on there for the fans. It so happens that back in the days of the 45 rpm record, there was a whole half of the vinyl record left over for the extra music; the side with the main song on it was the "A-side" and the side with the rest on is the B-side.

Even today, now that the 45 rpm single is more-or-less on the way out, the terminology persists. A B-side is a song released alongside a single. It may be a remix of the A-side, a song that's not good enough for release on an album, something too experimental to be commercially viable on its own, or just a joke.

The single is usually denoted as "A-side b/w B-side", the b/w standing for 'backed with'.

Occasionally, both sides of the single are promoted equally; the single is then called a "double A-side". Famous examples are "Strawberry Fields Forever/Penny Lane" and "We Will Rock You/We Are the Champions". B-sides may be collected onto Compilation Albums, or be included on an extra disc for deluxe reissues and Box Sets. They might also turn up as bonus tracks on later printings of the album.

In Japan, this is a requirement for many bands, in order to control piracy. It backfired. The Japanese Editions are among the most wanted (and thus, among the most pirated) editions of the albums.

Unscrupulous publishers used to cheaply buy the rights to B-sides of songs they predicted to be hits. Since the B-side got 50% of the airplay royalties, the publishers would clean up.

B-side songs may well become Black Sheep Hits.

Ubiquitous throughout the music industry, so examples should be parodies subversions or otherwise noteworthy.

B-sides

The B-side to Napoleon XIV's "They're Coming to Take Me Away Ha-Haaa!" was called "!aaaH-aH yawA eM ekaT ot gnimoC er'yehT" and was a backwards version of the A-side.
The Spitting Image single "The Chicken Song" b/w "I've Never Met a Nice South African" was jokingly promoted on the cover as a "double B-side", implying that both songs were of dubious quality.
Marvin released a "Double B Side" too.
Dance You Fuckers by Wall of Voodoo is one Hell of a b-side. Over 5 minutes long, it is the most Crazy Awesome track both line-ups ever recorded. Your mileage may not vary.
By his own admission, Jasper Carrott's "Funky Moped" only charted as a hit single because the B-side had a risqué The Magic Roundabout sketch.
Radiohead's B-sides are popular among fans for their strangeness and experimentation; "Kinetic" features a looped, backwards, slowed-down vocal part.
The Protomen released a white vinyl record roughly one year prior to releasing their Act II CD with the single "Father of Death". The other side contained a remixed version of "No Easy Way Out" from Rocky IV.
Blur have so many b-sides, that the situation is very close to Archive Panic.
Eye of The Lens by The Comsat Angels could have been their biggest hit in the early 80's, had it been included on an album.
Nightwish has a few of these from the Anette era, notably "The Escapist" and "While Her Lips are Still Red."
Self's "No B-sides": The back story is that Matt Mahaffey of Self was streaming one B-side (more accurately "outtake") from forthcoming album Ornament And Crime a day until the album's release date. When the anticipated release date came and the album didn't, the song for the day was "No B-sides", a catchy, jingle-like number where Mahaffey informed fans that there weren't any b-sides left, the album was delayed by record label issues but was still going to come out, and if anyone pirated the streaming songs in mp3 form, he would personally Groin Attack them. Now that Ornament And Crime is a Missing Episode, the song is a mild Funny Aneurysm Moment.

B-side compilations

Gorillaz have two whole B-side albums: G Sides for their self-titled first album, and D Sides for their second album Demon Days. They contain both unused songs and remixes by other artists.
Radiohead's My Iron Lung EP contains outtakes from the early stages of "The Bends" sessions. The only exception is Creep (Acoustic) which was a B side in the Pablo Honey era.
Elton John's Rare Masters collects his B-sides from 1968 through 1975 along with a few soundtrack recordings and other rarities.
Alternative by Pet Shop Boys collects their B-sides from 1986 through 1994.
Shits & Giggles by the Kleptones is a 2010 compilation of Kleptones b-sides from 2004 to the present day. The catch is that, as a mash-up artist, all of his albums have been released online for free and they've never had a proper "single". Also, it's damn good.
The Smashing Pumpkins' Pisces Iscariot and Judas Ø.
The Used's Shallow Believer.
Manic Street Preachers has Lipstick Traces, featuring their B-sides from 1989 to 2002.
Suede's Sci-Fi Lullabies is reckoned by many critics to be the equal of their better studio albums.
Oasis has The Masterplan, which contains many classics and fan favorites like "Acquiesce" that were never featured on their studio albums.
Pearl Jam has Lost Dogs, a two-disc compilation of B-sides and non-album singles like "Last Kiss".
Nirvana's Incesticide has many of their B-sides from the Bleach and Nevermind eras. Many fans consider it to be the album most representative of the band's style.
Green Day's Shenanigans.
The Pixies' Complete 'B' Sides.
Miscellaneous T by They Might Be Giants collects b-sides from their first two albums.
REM's Dead Letter Office, a collection of B-sides from their first four albums. Later editions would also include the out-of-print Chronic Town EP in it's entirety as bonus tracks. A deluxe version of In Time: The Best of R.E.M. 1988–2003 also included a disc of B-sides.
Disturbed's The Lost Children, released shortly after the beginning of their hiatus.
Disk 4 of Tom Petty and the Heartbreakers' box set "Playback" consists of B-sides.
Sugar's Besides

Double A-sides

Dolly Parton had several, including "It's All Wrong, but It's All Right"/"Two Doors Down" and "Baby I'm Burning"/"I Really Got the Feeling". Both sides went to #1.
Razzy Bailey also had two #1 singles with double A-sides: "I Keep Coming Back"/"True Life Country Music" and "Friends"/"Anywhere There's a Jukebox". "Midnight Hauler" also went to #1, with its b-side "Scratch My Back" reaching #8 soon afterward.

Famous songs that were originally B-sides

Boney M originally released "Brown Girl in the Ring" as the B-side to "Rivers of Babylon". Once "Rivers of Babylon" had become a hit and was slipping down the charts, they asked radio stations to start playing "Brown Girl in the Ring" instead — and then released that as the A-side of a single, with the B-side — what else? — "Rivers of Babylon". Effectively, many people ended up buying the same record again but upside down.
The song "Na Na Hey Hey Kiss Him Goodbye" (by "Steam") was written for the purpose of being the inferior B-side song for a number of A-side songs. It became a hit, while most of the A-sides were forgotten.
Vanilla Ice's "Ice Ice Baby" was originally the B-side to his cover of Wild Cherry's "Play That Funky Music," which was also a top five hit but not as big as "Ice Ice Baby."
"Move It" by Cliff Richard and the Drifters and "Shakin' All Over" by Johnny Kidd and the Pirates (the first British rock record and rock number 1, respectively).
"Beth", KISS' biggest pop hit, was originally the b-side to "Detroit Rock City."
ABBA's "S.O.S.", which was one of their first worldwide hits, was originally issued as the B-side to the mainly forgotten "Man in the Middle".
"How Soon Is Now?" by The Smiths was first released as a B-side and only later given a proper single release. This is commonly cited as the reason for its comparatively poor chart performance.
Gloria Gaynor's "I Will Survive" was originally the B-side to "Substitute."
Oasis's "Acquiesce" started out as the B-side to "Some Might Say". Such was its popularity with fans that it became a single itself a few years later (natch, it was as the lead-off single from The Masterplan, a collection of B-sides).
Red Hot Chili Peppers' Soul To Squeeze was the B Side to both "Give It Away" and "Under The Bridge" in 1991. In 1993 it appeared on the Coneheads soundtrack and was released as a single. Many people thought it was a new song, which was why the song was a hit.
Many songs by The Beatles were originally released as B-sides, including such classics as "Rain", "I Am the Walrus", "Revolution", "Don't Let Me Down" and "The Inner Light".
- Some Beatles albums managed to have the A-side and the B-side end up as #1 hits.
A really weird example is "Hey Hey What Can I Do?" by Led Zeppelin. The band was no stranger to releasing singles, however, none of them were non-album songs. This one, released as the B-side of "Immigrant Song", was, and yet remains a beloved radio staple to many a Zepp fan.
"Incense And Peppermints" by The Strawberry Alarm Clock. "Birdman Of Alkatrash" was its original A-side, but radio DJs preferred the flip-side instead.
An abridged version of "You Can't Always Get What You Want" was the B-side of The Rolling Stones' "Honky Tonk Women". When the full version was released on Let It Bleed, it became just as popular.
"Dear God" is one of XTC's most well-known songs, but it originally was the b-side to their single "Grass". Once it started unexpectedly getting radio play, it not only got it's own single, but it also was added to the album Skylarking, replacing the album track "Mermaid Smiled". The most recent reissue of Skylarking includes both, though: "Mermaid Smiled" is in it's original place on the album, while "Dear God" is included as a bonus track.
A near example came while George Harrison was working on doing a B-Side for a single off his new solo work. Visiting with his friend Bob Dylan, who had a mini recording studio in his place, he ended up doing a little song along with a few other friends, Roy Orbison, Jeff Lynn and Tom Petty, taking the name from a tag on one of Dylan's travel cases. When he sent it to the record company, they saw imdiately that this was NOT a B-Side song and asked for more. The result was that Handle With Care became the lead song of The Traveling Wilburys.
Pink Floyd's Careful with That Axe, Eugene".
Elvis Costello & The Attractions' cover version of Brinzley Shwarz's "(What's So Funny 'Bout) Peace, Love, and Understanding", which came to cover up the original. Not only was it originally a b-side, but it wasn't even a B-side to an Elvis Costello single - it first appeared as the B-side to "American Squirm", a single by Nick Lowe, who wrote "...Peace Love And Understanding".
U2's "Sweetest Thing" was originally a b-side to "Where the Streets Have No Name" in 1987. Eleven years later they re-recorded it for The Best of 1980-1990 and that version became a sizable hit.
Chicago's "Colour My World" was a B-side twice; it backed "Make Me Smile" in 1970 and "Beginnings" in '71.
Alan Jackson used "Home" as a b-side for five songs before releasing it in April 1996.