Image Boards: the various banners at the top of the page often mocks the site itself. Users often use this as well:
They will generally poke fun at the stereotype that all of its members are socially inept, perma-virgin,shut-ins, and the humor may also vary depending on the particular board. For example, posters on /v/ will joke how having fun while playing a game is wrong since they all suck, new and old, and the main fitness guide on /fit/ assumes that its readers are most likely social failures and how obsessive /fit/ members are with the littlest of details in fitness and diet practices.
The pejorative term "fag", is used frequently as a suffix when referring to groups. When introducing themselves in a post, many users may point out that they are a Xfag, with X being an arbitrary group. While referring to another group as "Xfags" may be used as an insult, it is more frequently used as a non-hostile way to refer to oneself or another group.
"You're watching the Ebolaworld Channel. Why are you doing that?" "You're watching the Ebolaworld Channel. W..What?" "You're watching the Ebolaworld Channel... Weirdo!"
The Busy Street Mailbags, where hate mail sent by those aggravated by the site are picked apart, is usually accompanied by self-deprecating humor, with the commentators acknowledging the faults and weaknesses in their articles while mocking each other in good humor.
Cracked.com is fond of this, often saying how advice for living your life is coming from internet comedy writers, and then there are asides that raise questions as to the sanity of said internet comedy writers.
Many of Daniel O'Brien's articles are all about how much of an asshole he is. And Robert Brockway's tend to end with either him or the reader arrested for some outrageously drug-fueled mischief.
The Dead Horse Interchange staff frequently make reference to their "internet has-been" status, their self-described perma-virginity, greed, lack of talent, and inability to maintain frequent updates. Ebeeto is an "understimulated hermit Swede", Monty is a "Charlie Brooker-lite alcoholic teenager", and Schlasser being a "ripoff of The Angry Video Game Nerd".
In Whateley Universe stories, most of the canon authors have an Author Avatar. All of them are members of the Whitman Literary Girls, all have annoying characteristics, and all of them wish they were the big heroes who get to save people and stuff. They're not.
Phase constantly puts himself down by comparing himself to his friends, other, more powerful students, and superheroes. Thing is, he's an incredibly powerful character, has a number of very versatile attacks, and is continually shown to be much better in nearly every aspect than he thinks he is. Poor bastard has no self-esteem.
While The Nostalgia Critic often doesn't take himself seriously, the majority of his snark tends to be the movies and TV shows he reviews. To make up for it, he created an episode devoted to times he did something particularly embarrassing. Top 11 Fuck-ups
During his review of Jack Frost (1998), he mocks the article done about him on Entrepreneur magazine saying "They'll print anything these days".
Over the course of his reviews, he's been socially awkward, seriously obsessive about his childhood (which really seemed to suck for bigger reasons than just bad movies), goes on rants about "dreams not coming true" and sometimes not all that bright. Doug does love making his main character a mess.
In his tribute to Siskel And Ebert, he responded to Ebert's claim that Congo was intentionally So Bad, It's Good by sarcastically saying that Dominic from Video Game Confessions had a good Cockney accent
When Mara Wilson became peeved at Doug for mocking her acting, he wrote a list of insults that she could use on him if she wanted. She also had guest spots in later That Guy with the Glasses reviews of her movies where she wreaked horrible vengeance on them. (the first even brought the Critic's self deprecation further, as she replied to him criticizing her as a child actor by showing off his embarrassing teen videos - Doug deliberately picked the worst ones)
The Nostalgia Chick's "Thanks For The Feedback" videos paint her in a rather pathetic light, first with her best friend Nella saying that at least going on a date with the Critic will mean leaving the apartment for a few hours (her response is "We haven't watched the My Little Pony movie in three days!"), then answering the question of why Nella puts up with all her mistreatment by showing that the Chick pays Nella to be her friend and shore up her fragile self-esteem.
And of course, related to the above mention of Mara Wilson she co-reviewed Matilda with the Chick.
In their RP of Policenauts, Diabetus comments that the only thing sadder than reviewing the game would be hacking it. Slowbeef, who was working on a translation patch for the game at the time, commented "I'll sa—fuck you."
Many good Let's Players do this almost constantly. Common subjects include the infrequency of their updates/uploads, their voice/recording setup, and the vast amount of time they use to produce the videos instead of doing something productive.
A lot of Slashdotters crack jokes about living in their parent's basement, not having any love life, etc.
Similarly, Diggers make similar jokes, since one cannot have sex on the internet.
The Something Awful Forum Goons are pretty fond of this as well, but then again they don't take much seriously in the first place.
Most of the more self-aware Abridged Series do this, occasionally with the creators guest-starring on other people's Abridged Series in order to make fun of themselves.
LittleKuriboh of Yu-Gi-Oh! The Abridged Series does this pretty consistently. In one extreme case the characters wondered where he had gone for four months. Another time, he parodied his own proposal video and had his characters wonder what kind of "sick, lonely person" would do such a thing. In a later video, Yugi and Yami complain about LK's incredibly boring voice.
In JourneyQuest, at the end of episode 7, Wren the bard is trying to figure out what to name her epic (which is about the series' events). She comes up with "Journey Quest", then discards the title.
Wren: I have to give it a name! Uh... well, it started out as a journey, and then it just kinda became this whole different quest... journey, quest... Journey Quest!... ugh, that's terrible.
While the persona Yahtzee of Zero Punctuation assumes in his videos, is that of a quite pompous, sarcastic, caustic critic, he often take pot-shots at himself, especially his awkward relationship withsexuality, and fully admits to often falling prey to some of the same shortcomings that he frequently criticizes developers for in his own games and writing.
Yahtzee: When you review games for a career—shut up, it's totally a career . . .
Key of Awesome's "Moves Like Jagger" parody illustrates the apparent difficulty of imitating Adam Levine by having Mark sing about being too fat to perform the parody, and Todd about being too weak. They end the song by calling themselves "attention whores" who will "do-o-o-o-o-o anything for laughter."
FIMFiction.net has had a lot of trouble with 502 errors. So much so that, for a time, they replaced their title banner with:
"502Fiction.net. We sometimes serve fanfiction."
TV Trash: In Rowdy's review of "Happy New Year Charlie Brown", he remarks that Charlie Brown was his dating guide. "I'm going to die alone!"
In Ultra Fast Pony, Wacarb frequently mocks his editing or lip-synching by slapping a "Quality editing!" subtitle (or some humorously misspelled variant) on scenes he considers sub-par, or by using a "This looks familiar..." subtitle to mock his overuse of certain clips. In "The Longest Episode", he takes a big swipe at the writers of the source material, then follows it up by implying that he's even worse.
Celestia: Whoever wrote this episode must have had brain damage. Twilight: Yeah, I think all the writers do. Subtitle: That's why I don't even have a brain!
In Google, you can start typing "why google s" and one of the term suggestions is "Why Google sucks". If you type "google is", two of the suggestions will be "Google is evil" and "Google is making us stupid". Typing "I hate g" will instantly show you "I hate Google". And so on.
Youtuber yuriofwind often makes fun of his clinical depression, colorblindness, and stupid username. He'll also occasionally bring up an insulting comment from a previous video to verify that yes, it's true, but irrelevant.
SWAG.MOV has a Freeze-Frame Bonus appearing during a particularly ridiculous (even by the series' standards) scene, a giant bipedal Rainbow Dash summoning an enormous sword from the skies above with which to slay Discord.
THIS IS SO FUCKING RETARDED OH MY GOD I CAN'T BELIEVE I'M ANIMATING THIS.
SF Debris's Chuck Sonnenburg after spending the first eight minutes of his review of Transformers talking in deep detail about how the relationship of the summer blockbuster to science fiction is both blessing and curse. After the commercial break:
"Okay, I stand by everything I have said, and I do advocate rational discourse over a hurricane of trolls. But I'm also an Internet critic and part of the job is, well, this part of the show now, where I act like a guffawing dickhead."