I was reading an interview with Jimmy Wales (the Wikipedia guy) in Selling Power magazine (I have ecletic reading preferences I know) and aside from the stuff about Wikipedia he talked a little about moving into search and how he hoped that by leveraging the lessons learned so far he might be able to produce better search results. That's an interesting idea if he can get it to work. I think Google is probably still the leader at search, but not by as much as they used to be. Search is almost a commodity. Almost! But there is still a lot of luck involved. Can a community approach remove the need for some of the luck? The wild card is the advertising. Advertising drives most of the gaming of search results, remove the advertising and people (and companies) would spend a lot less time on trying to increase their PageRank or equivalent score.
Wikipedia may not be perfect, but I find it helpful probably 95% of the time. Given the choice of working there or Google, I'd go with Wikipedia because I love the community aspect.