There's a phenomenon going on on Youtube called "poop" or "Youtube poop."
If you don't know what it is, you should take a moment to look it up...
Basically, "poop" generally involves taking a scene from a show people have hopefully seen before, and reproducing it with modifications. Often, a simple repetition of the clip for a good twenty times is the entire video. Other times, the video will involve taking that clip and visually modifying it in cliche ways like inverting it or blurring it etc. Sometimes the speed of the clip or only its sound will be modified: sped up or slowed down are the most commonly used and simple modifications.
And I should say that my interpretations of humor generally include the premise that laughter is an "all-clear" signal, and the humor is derived from situation which at first appear serious but then are revealed to have been not serious. It removes threat.
Traditionally, taking a scene or comment or sound bite out of context is done for an educational and/or informative purpose. OK, there are humorous clips too. But when repetition is involved, it is usually for a purpose. People scrutinize a surveillance tape or memorize spanish etc. because repetition does aid memory and understanding.
But what about when things are repeated for no good reason? Even a joke that's repeated loses humor value when you re-tell it. "Poop," on the other hand, gains humor from being repeated. This is because the repetition is obviously trivial. The creator and the viewer both know that there is no value in memorizing the scene, and no new information is being presented. It is a farce, a joke played on our sensibilities on a fundamental level.
One achieves the same effect by changing the scene in trivial ways. Some examples include color tints, pixellation, inversion, and a myriad of other techniques that usually add some sort of meaningful ambiance or purpose. When used in this style of "poop" humor, however, the modifications are obviously trivial and largely arbitrary. Speeding it up or slowing it down, for example, provides no new information, even though it indeed sounds or looks like a new piece of information. Usually a modification is added after the original scene is repeated non-modified at least once or twice. This unconscious technique really asserts that one is perceiving something in a new way but gaining no new useful information or understanding. It is important that the viewer believe the creator acknowledges the triviality of the repetition or modification, or the joke might be interpreted as pure idiocy.
This sort of humor exists in non-youtube form as well. Peter Griffin in Family Guy trips and hurts his ankle, whereupon he sits in pain for an uncomfortably long time. Also used in Family Guy in other situations, even in direct parody of the repetition technique for education, as in the scene where "back and to the left" from JFK is repeated more than in the movie itself (and taken out of context it is clearly a joke). Grim Adventures of Billy and Mandy also use the humor, and I believe the "Dude, where's my car?" "Where's you car, dude?" scene (from the movie by the same name) is another example of how obviously pointless repetition and arbitrary modification is seen as humorous.
Really, in the case of "poop," what is subverted is the seriousness of the very act of attempting to make meaning out of what we see.