eBay already has a thriving user community of buyers and sellers, and they have found yet another way to leverage this community. The eBay Wiki Beta is a place to share knowledge about any relevant eBay topic providing a way for users to share tips and tricks with other users. This is brilliant on eBay's part. They have a devoted community made up of a combination of casual users and quite a few frequent sellers and buyers, including some people who make their living buying / selling on eBay. eBay has only 11,600 employees, but they have over 100 million buyers and sellers around the world. The eBay Wiki provides a great way to harness the combined knowledge of these users to help other users navigate eBay in an open, community environment. Richard MacManus also has a good review of the site including an interview with Joe Kraus of JotSpot, the company working jointly with eBay to provide the wiki technology.
Some of the articles already posted include how to efficiently manage images on eBay, ways to recognize fraudulent transactions, using the eBay toolbar, and many more. From a business perspective, this is a win-win for eBay. The wiki provides the information that new users need to succeed and become active community members, and at the same time, the community members who contribute to the wiki are spending more time on the eBay site.
Right now many of the articles are written by eBay employees; however, as the wiki gains traction, I would expect for more and more people to contribute. The community already exists, but the wiki provides a forum that allows the community to be more effective and more involved in eBay.