Have been following the series of facinating articles by Google Scientist Jun Wu on Google China's Blog site:

http://googlechinablog.com/2006/04/blog-post_10.html
http://googlechinablog.com/2006/04/blog-post.html

Found the Google way of doing things:
1) Collect feedback by search
Great idea! What can you expect from a seach-centric company?
Never quite understand how to use trackback or pingback anyway. Need a good filter though, because those advertisers will figure out this soon. Johnny Ding has more details on this:
http://spaces.msn.com/johnny-ding/Blog/cns!72DC1EBA6DE56B11!110.entry

2) Leave no place for comments!
Don't quite understand the motive. My guess is that spammers are taking advangtage of those spaces to put their ads in all the blog comment boxes.

BTW, I noticed that most feedback is from MSN Spaces users.