Amazon.com has launched a wiki website about products called Amapedia. Entries about different products are tagged two ways on Amapedia. Products are tagged with terms that describe what the product is. There are also tags for the product's most important features. O'Reilly Radar says Amapedia launched with 5,000 articles.
It launched with approximately 800 internally created articles and 5000 articles that were ported over from the previous version. As you click-thru the site you will quickly realize just how empty it is and how many fact & category tags have not been filled in yet. Try playing with the random article functionality to take a spin through the site. The article pages are very nicely crafted. The tags are on the left. The article text and images take up the majority of the page.
O'Reilly also points out that according to Amapedia's Terms of Service Amazon owns all rights to Amapedia entries just like they do for the product reviews on the Amazon.com website but people can still use their own content elsewhere.
If you do post or otherwise submit questions, answers feedback, or any other content, and unless we indicate otherwise, you grant amapedia and its affiliates a nonexclusive, royalty-free, perpetual, irrevocable, and fully sublicensable right to use, reproduce, modify, adapt, publish, translate, create derivative works from, distribute, and display such content throughout the world in any media.
Amapedia's FAQ pre-answers a question many might be thinking. Since Amazon already has a massive amount of product information why do they also need a wiki collecting product information? Here's Amazon's answer.
your favorite products; only you can tell us which ones they are
product information that comes from you, so that it might be more impartial and authoritative
product facts that actually matter to you (like shutter lag for cameras and fan noise for notebooks), not those supplied by manufacturers or sellers.
Those are some good reasons. Amazon was also probably worried that if they didn't start owning and providing this type of user generated product information people might go to one of the many social shopping startups to find it instead of to Amazon.com. If Amazon's Amapedia experiment works maybe they will eventually incorporate the wiki content into their product pages on Amazon.com. More discussion of Amapedia can be found at Workbench, Read/WriteWeb and Business 2.0 Beta.
Amazon.com has launched a wiki website about products called 
