Right now, I'm seeing VW (virtual world) as having a commons area. This area would have characters from multiple worlds, though I imagine main characters would generally stay in their respective worlds. This commons would be the area you "spawn" in when you first enter, and might function as a sort of hub town, with shops and such. From the commons, you could go to separate canons. Going to a canon would make you a character that fits n that canon (so yes, I figure we'd probs turn into ponies.) Most canons would keep you human, though. I don't think you'd become a main character, you'd just be the average resident.