Yesterday's Wall Street Journal affirms this belief, with an article about the growth of professional social networks, including one for our industry called AdGabber, that I'd never heard of, but seems to be a subset of AdRants, and which seems to be more of a traditional message board than a LinkedIn-esque networking site.
Though the article doesn't make a clear distinction between message boards and blogs and actual social networking sites, the line between them is getting blurrier by the day. But bottom line is that the ability to reach out to colleagues from all over and discuss issues related to work is something that continues to have great appeal.