Rosalind - 4:16 pm on Dec 14, 2007 (gmt 0)

1) Google will be competing with significant numbers of high-traffic sites that have already built communities of contributors: e.g., Wikipedia and other wikis, "experts" sites, TripAdvisor, and so on.

Yes. I'm wondering whether this will actually do anything to increase the amount of user-generated content in the SERPs, should it become successful. Perhaps it could just split it in two, or perhaps divide the exposure of these websites.

After all, there's a limit to the proportion of people who are really interested in contributing to the internet in this way, and a limit to the amount of time they have to do so.