In Silicon Valley these days, it seems that one out of every two people you meet either works for a social network, writes about one or has invested in one.

But few people have analyzed and dissected how social networks will impact business than Charlene Li, an analyst with Forrester Research.

Li has been blogging about social networking and related trends since 2004. With her colleague Josh Bernoff, she's co-authored a book that shares the same name as her blog, Groundswell.

The big-picture idea is that social networking technologies are creating a groundswell of change that will sweep across corporate America as more workers use social networks to network and communicate.

We caught up with Charlene in Mountain View this week at an Under the Radar event she was judging and asked her to give us the big takeaways from the book, which has been selling well so far on Amazon.com. 

A few months ago, Charlene gave her advice to startups on how and when to pitch to a research firm like Forrester.