Scriptshadow, which obtained the first leaked script for Facebook movie The Social Network, now claims to have casting choices, including Justin Timberlake as Napster's Sean Parker. News In Film created this handy graphic.
Jesse Eisberg kinda works as Facebook founder Mark Zuckerberg, we guess. But how about Michael Cera, instead? With some hair-curling he'd have the look down, and he could have used the role to break free from the "twee teenaged dork" typecast and into the much more interesting "Asperger-level-antisocial teenaged computer nerd" role.
Got a better casting idea? Post it in the comments.