Beat the Recession with Tip Jar

Wikipedia has long leveraged the wisdom of crowds. Similarly Google's Tip Jar, probably built during some Googler's 20% time, gathers money-saving tips in one place and invites people to rank them in order of usefulness with the expectation that over time, the best and most useful tips will rise to the top.

StackOverflow, the programming Q & A site, is another such website that provides superior answers through a similar ranking system where users vote for best answers. StackOverflow also has an interesting reputation system.