One kind of roleplaying that is getting a great deal of new attention these days is "machinima." For those who don't know, machinima is basically a kind of film in which people use the game's existing 3D models and environments to make their own movies, and then share these movies with everyone on the internet (or very rarely on TV). As we have seen here at WoW Insider and elsewhere, these movies are especially powerful as comedies and music videos, especially for viewers who are already familiar with the game that they're made with.
But for most people who roleplay, it is not a scripted performance, but an improvised one; it is not carefully lip-synced, edited recorded and for all to see, but imagined, written out, and remembered only among those who played the parts. Someone not familiar with roleplaying might wonder why people bother with it.