Deadpan Snarker/Web Original

"A 30-year-old heavyweight takes on a 50-year-old dictator? Gee, I wonder who's going to win!"

That Guy With The Glasses. A large portion of all the sites reviewers have a Snarker tendency. The Nostalgia Critic in particular provides the page image.

Guile: I'm going to get on my boat, and I'm going to kick that son-of-a-bitch Bison's ass...
The Nostalgia Critic: Heart of a poet.

- The Surf Ninjas review. A whole episode of snarkiness. WOW.
- The Cinema Snob has such a great voice for it, too. Case in point from his Island of Death review, when he sees a character get brutally slaughtered with a knife and a gun, then another character says that they don't know how he died.

Snob: If only the stab wounds and bullet holes had given us more clues!

This guy is pretty sarcastic to his father while he's making himself ready to hang himself with his tie. Then again, that's pretty understandable after reading My Immortal.
Yu-Gi-Oh!: The Abridged Series is full of delicious snarkiness, especially Kaiba, Yami Yugi and Bakura, though everyone gets their snarky moments
Sarah in Lonelygirl15 and, to a much lesser extent, LG 15 The Resistance.
Drake from Bronyism is all about this trope.
Shadow the Hedgehog in Super Mario Bros Z, compared to in the actual Sonic franchise.
The title character of Joss Whedon's Dr. Horrible's Sing-Along Blog. (See the page quote)
- His sidekick Moist...

Dr. Horrible: I have a PhD in Horribleness.
Moist: Is that the new catchphrase?

John, and to a lesser extent, Dave, from John Dies at the End.
Jeff Andonuts, hands down, in Fobbies Are Borange.

Jeff: Isn't your mom's name Rosie?
Paula: Well, yeah...
Jeff: Rosie the robot. He took the name from the Jetsons. Your mother is a robot, Paula.

Common both in and out of character in Survival of the Fittest. One of the better examples would be Sean O'Cann, at least in his moments of clarity.
Dr. Shelton in Darwin's Soldiers.
Ben Croshaw very rarely feels the need to be deadpan--his humor's most often very blatant. Every so often, though...
Danny Brady in Shadow Unit often fills this role, and so does Daphne Worth from time to time--usually when she's trying to outdo Brady.
Professor Otaku frequently uses this, but it's also aided by the fact that he lacks any sort of smiling facial expression. Growing up on Spider-Man comic books probably didn't help.
As Unskippable's premise is based off of Mystery Science Theater 3000, it's only expected that the two hosts play this role to a T.
Curt, from Mirrorfall definitely counts. In response to being teleported with Stef into the infirmary where the resident twin doctors are engaging in some, ah, 'creative healing' he covers Stef's eyes and says when she protests, "‘Newbie, don’t ask unless you want to see a very explicit answer to the question “what’s up doc?”
Left 4 Speed 2's Nick. "A mall. How original."
Los Hermanos, a member of the titular Global Guardians superhero team, is probably the most notable heroic example in the Global Guardians PBEM Universe. The most notable villainous example is likely The Evil Mastermind (a hyper-intelligent, nine-year-old Gadgeteer Genius and leader of Evil Mensa). When the two of them face off, it's a veritable hurricane of snarkiness:

The Evil Mastermind: "Now that you're in my clutches, hero, I'll..."
Los Hermanos: "... bore me to death with the gloating and the grand-standing? You're like a villain out of an old-style movie serial."
The Evil Mastermind: "Oh dear, your use of a reference to a form of entertainment that hasn't been produced in sixty years has destroyed my self-image. What will I do now?"
Los Hermanos: "Go back home and finish your homework?"
The Evil Mastermind: "Ooh! And now comes the crack about my age! You know, that's almost but not quite completely ineffective! But please, do keep trying. It's always important for people to think they're accomplishing something..."

Oancitizen. His field of expertise (arthouse movies) provide ample material.
Phase does this with references most of the rest of the cast doesn't get. They return the favor. Girlfriend stuffed in a fridge, anyone?
In his podcasts and website, skeptic Brian Dunning actively uses deadpan snarking in his articles.

I have no idea whether a single atom of magnesium restores sex hormones, whatever that means, but if so that's one hell of an atom. If you want magnesium, take a vitamin pill. If you want oxygen, take a breath. If you want sex hormones, get a girlfriend. -Wheatgrass article

Ferr.
BikdipOnABus can be this sometimes, especially to stupid commentors.
Pixel Girl of The Defrosters actually claims to be this in the first episode of the new season. She also claims to be a troper.
The Bugle is what happens when you put three British Deadpan Snarkers on a trans-Atlantic call once a week.
Both friends from Two Best Friends Play fluctuate between this and open hostility at whatever they are playing.
Dana from Echo Chamber.

Shannon: Shut up! You just don't know anything about love!
Dana: Oh no. My heart. She breaks.

The reporters for Yahoo's Odd News, especially Greg Proops, make humorous comments on everything they report about.
Moose from Chicken and Moose.
The Angry Video Game Nerd is famous for the sarcastic remarks he use when he's reviewing bad games. Half the fun of the show is his very deadpan personality. As snarky as he is, he might should be the Trope Namer of this trope.
Stuff You Like's Sursum Ursa usually leaves the sarcasm to her subtitles. Usually.

Sursum Ursa: Because we cannot ever, ever, have ugly people on our screens.

The Agony Booth's Mr. Mendo does this in his reviews, but really shines when dealing with hostile commentors. For example, after someone took issue with him trying to prove that Forrest Gump was a bad movie, he responded:

Mr. Mendo: You're right, I should never have the courage of my own convictions. It's bad manners, you know...

MSF High Forum: Miranda by a mile.
Protectors of the Plot Continuum use this trope as a survival mechanism.
Alex from Marble Hornets.

Alex: (after his house had been broken into) Hey Jay, you forgot your flashlight.

Fan works:

Almost everybody is this in both Aeon Natum Engel and Aeon Entelechy Evangelion, even Rei.
In DC Nation, Green Shield and Caleb Zukov take snark to the level of art form - usually at the other's expense.
- Anything by Itsjustsomerandomguy, especially the Joker and the Green Goblin (when he isn't high).
In Kyon: Big Damn Hero, Kyon managed to be more snarky than usual.

Kyon: Oh, wow, the fight went bad, so you pulled out a knife! What a brilliant and wholly original tactic!

New media:

The website Cracked.com is the epitome of this archetype.
- So, it comes as no surprise that David Wong writes for that site.
Sylvester, from this YouTube video.
Peter Paltridge, the host of Platypus Comix, works a number of sarcastic and/or smartass remarks into his articles.
Snark has a certain cathartic or ego-stroking value for many people especially if it seems to go over the heads of their targets. For this reason and also because of the GIFT, many netizens will snark as much as possible at anything they come across. Attempts are often made to veil genuine anger at someone else's snark with one's own cutting wit, usually with cringe-worthy results.
- Admit it. We Tropers are a snarky bunch.
- People on Facebook either ignore utterly pointless or vague statuses, or deliberately make fun of them. There really is no in-between.
- Many YouTube commenters will show up on a video that does not interest them at all just to snark at the fans (or the fans' comments).