In my experience, there aren't tools who fill the two gaps you're talking about here, and traditional CRM tools don't fit.
IMHO, you'll have to use a Social Media Monitoring framework - you start with monitoring in order to identify peers, influencers, do a sort of sentiment analysis. And them, you can use a sort of Social CRM tool ( like Batchbook or Highrise) in order to create a central database of people.
Two awesome articles to follow and improve your social media strategy:
1) Listening framework - http://www.web-strategist.com/blog/2009/11/10/evolution-the-eight-stages-of-listening/