Why Would People Contribute to Wikia?

The idea of creating community is not a place where people sit around and chat on a chat board. It's about bringing people together around things that they're passionate about. The validation of other people who are equally passionate about restaurants in Italy says, yeah, you're right. And I'm doing it for a selfish reason, which is I think if I publish enough information about something I care about, other people will find it and add to it.