Twitter just might be doable. Facebook’s demographic is over half the nation, with a large segment over 35, but you’ll be bombarded by trivial emails from others asking you to join their group(s). The whole key to the Web2.0 (social) sites is to build a following so you can direct them to other webpages of interest. If you have the dedicated staff, like a 60 person small online research/publishing firm, then it can be an effective strategy.
Co-ordinating media opportunities like articles, press releases, and videos are proven ways to build awareness of anything- FF, the blog, the twitter page, the facebook page, I’m sure you can see this devolving into the nth dimension as Eric mentioned.
