Buzz API. Search. Results returned in Atom. I'm sure somebody can find a use for this. eg
http://www.googleapis.com/buzz/v1/activities/search?q=commenter:julian.bond
http://www.googleapis.com/buzz/v1/activities/search?q=buzz+api
And check out the extra parameters eg &lat=latitude&lon=longitude&radius=radius
http://code.google.com/apis/buzz/v1/using_rest.html#search-activities