Can someone explain to me how the Social Network movie is so popluar?

It’s a movie about Facebook for those who aren’t aware. I don’t get how it’s that interesting a film to warrant the top spot in the weekend box office for two weeks in a row. Has anyone seen it that can help me? I’ll give Facebook a little credit for being a way to find old friends, like my mother uses it for. There’s no movie about Myspace or Twitter. I do not get why it’s such a big deal it needs to be made into a movie.