Important Update: Jimmy Wales posts in the comments to say that Amazon is NOT involved with the Wikia search project. See this page on Wikia for the details.
Wikipedia founder Jimmy Wales is set to launch a search engine early next year in partnership with Amazon - it's intended to be a rival to Google and Yahoo. The Wikiasari project may launch as early as Q1 of 2007, using the same user-generated system as Wikipedia. It will be a for-profit project launched by Jimmy's company Wikia. "Wiki" as Wales has told just about every interviewer for the past 5 years, means "quick" in Hawaiian - "asari", meanwhile, means "rummaging search" in Japanese.
The problem Jimmy Wales faces is that Wikipedia was such an unparalleled success - that success generates high expectations for his newest projects. Social search has been tried a number of times and failed, largely due to a lack of motivation on the part of the "editors" and the fact that Google is generally considered to deliver high quality results.
Digg is another point of comparison: although it began as a fun way to rate the news, problems arose when people realized its influence and ability to generate ad revenue for the sites that get Dugg (Digg users don't click ads, but most sites still sell their ad space based on the number of monthly pageviews, not to mention the number of inbound links a front page story on Digg can generate). Just as Wikipedia is controlled by a number of power-players, Digg soon became the domain of a handful of top users, who can get anything to the front page due to their massive number of friends. Digg even figured out how to limit the power of these top users, but decided to reverse that move since they considered the allegiance of those users too important. There's even more money to be made from having the top result on a search engine, and it's 100% certain that these issues will arise.