For those who haven't seen these floating around over the past few weeks, each trailer is rather amusing. I've embedded all three videos below.
The first one is for "The Social Network", an actual film being released later this year that documents the rise of Facebook. Trent Reznor of Nine Inch Nail's fame has signed on to do the score of this film. It is scheduled to debut in theaters on Friday, October 1.
The second trailer is a spoof of "The Social Network" trailer, profiling a fictional film about the creation of YouTube.
Finally, the last trailer also parodies "The Social Network" trailer, but this time features Twitter as the subject of a fictional film.