With Release Candidate (RC0) of SQL Server 2008, we have now enabled the Community Content feature on the SQL Server 2008 Books Online. This is the same feature that has been enabled on the SQL Server 2005 version of the documentation for about a year now.
While not intended as a means to ask questions and get answers (please use the Forums for that), if you want to add additional information, such as a sample, then by all means please do so!
Here is a really good blog posting from an MVP about how he uses the wiki and the value that can be derived from it: http://tfl09.blogspot.com/2008/06/msdn-wiki-1100-edits-later.html.
SQL Server User Education