Internal representation is different from display representation. So long as it looks good on a screen, I don't really care what the markup looks like. You can

Internal representation is different from display representation. So long as it looks good on a screen, I don't really care what the markup looks like. You can then represent it internally in any format that you want. XML sounds good, because it is completely general, but that generality can also be a curse (due to its self descriptiveness, it is pretty much never the most compact way to represent structured data). Screenwriters are old fashioned, but will definitely come around over time (just like filmmakers are slowly switching to digital). There are already web apps that allow you to write screenplays online - http://www.scripped.com http://www.scripped.com is one. I'm sure that, in the long-term, the collaborative aspects of the web will trump any technical difficulties.