In 2003, when Mark Zuckerberg's girlfriend, Erica, breaks up with him, in a drunken rage he writes a very scathing blog about her & creates a website that rates one girl against another for attractiveness. This starts the beginnings of the"Facebook" idea. His "Face Mash" idea brings him to the attention of the Winklevoss twins & gains a job as the programmer of their website Harvard Connection.
Mark borrows money from his friend Eduardo to help start the Facebook idea of his and uses his club to become popular. Mark is very sly & builds his own website for personal gain & forgets about Eduardo & the twins, leaving them out.
The framing device throughout the film shows Mark testifying in the two lawsuits by Eduardo & the twins, which he had to settle.
The funny part at the end was Mark trying over and over to befriend Erica (played by Rooney Mara - star of the upcoming American version of The Girl With The Dragon Tattoo movies) on Facebook.