Building Community

here are some tips on building community...
http://fortuito.us/2007/05/some_community_tips_for_2007
http://www.problogger.net/archives/2006/10/12/10-techniques-to-get-more-comments-on-your-blog/

as an example of getting users to comment, here is a great post where the author shares his recollections and at the end asks the readers to "Share you Apple recollections in the comments." This got far more than average comments.
http://www.techcrunch.com/2007/06/05/30-years-of-apple/