While the goal of this site is to focus on banking, there are a lot of really good experts out there talking about social media. I recently came across a blog post on the Web Worker Daily site called "Tips from the Trenches: Using Social Media in Business". The themes are pretty consistent with our experience:
1) Jump in and try it first.
2) Listen and learn.
3) Be authentic.
Once you are in the space, then determine if and/or how it will best work for your business objectives. I think the "Ready, Shoot, Aim" approach may summarize it nicely.