I'm going to disagree and say Google hasn't had many neat ideas in years. I can't think of anything they've done recently that's had anywhere near as much impact as PageRank, AdSense/AdWords, Google Maps, or Gmail. All of those were released in 2005 or earlier.
Knol is a tweaked Wikipedia. Lively is a Second Life clone. Open Social was the response to Facebook Apps.
Chrome, Android, and maybe App Engine are the only recent things I can think of that have any potential.
So google, a company that prizes automation and data-driven decision-making over subjective filters and editorial oversight....doesn't do so hot with community-driven projects?
Not so surprised.
I dunno, I get a warm feeling when stuff like this flops for them. Shows they're human. They probably learned a great deal that will be applied elsewhere.
Maybe (hopefully?) Knol is next.