It's kind of like Stripcreator in a way... Like how on average everyone on the site has between 1 and 2000 cowboy physics takeoffs.
That one you just posted for example, is one in a vast series of sites that are taking off from an idea of something traveling really fast set to that one crappy techno loop with the phrase "LOL _____". I think the reason people like that one so much is a combination of fast sinking + underwater muffling of the crappy techno loop. It's mildly amusing in context, I guess... but without the context, there's really nothing funny about it.
Really though, I really don't get what's so funny about the premise of that particular "joke" in the first place.
For that matter, I don't even get what's supposed to be funny about the original ytmnd page. How in the hell it sparked anything is completely beyond me.