I found this blog on Duct Tape Marketing that has some really positive numbers about social media adoption by small businesses. It might be helpful (I know I am going to use it with some of my clients) if you have clients who are small businesses and don't think that social media is a small business kind of thing.

http://www.ducttapemarketing.com/blog/2009/10/15/survey-finds-small-business-adopting-social-media-rapidly/