And, I definitely agree...the tactics vary a bit. But, I have had much success in social media for B2B and B2C. As Brandon and I were discussing the other day - even a CIO is a consumer!
The channels you use and the approach you take is a bit different. But, bear in mind, different doesn't have to mean stuffy and boring. Look at the viral campaign that Agency Fusion did: http://makemylogobiggercream.com/
Their customers are marketing, graphic design and ad agencies, so that is B2B. But, they found some humor in that business. I'm not saying that kind of approach will translate to every area. But, the fact is just because someone operates in B2B does not mean they check their sense of humor at the door. People are people right?