I guess they're reading this.
'Cause that's what Radian6 does; it reads tiny little blogs (and big ones), and all other manor of social media, finding what people say about its clients. I would have thought you could just do this with google, technorati and maybe a few phantom flickr and facebook accounts. Maybe they do? But they hint that they have a substantial back end.
This is a nice article as it doubles as both a look at where social media meets PR, and it profiles the unique strategy Radian6 used to launch their start-up. They gave it away for free to a small, local sub of a global PR firm, in exchange for feedback (and cred.) It worked brilliantly.