Merrick Morton/Columbia Pictures Jesse Eisenberg as Mark Zuckerberg, the founder of Facebook, and Rooney Mara as his girlfriend Erica in The Social Network How long is a generation these days? I must be in Mark Zuckerberg’s generation—there are only nine years between us—but somehow it doesn’t feel that way. This despite the fact that I can say (like everyone else on Harvard’s campus in the fall o