I'm enjoying reading Ian Delaney's write-up of the Virtual Worlds Form which took place two weeks ago in London. I'm openly a virtual worlds fan (and used to PR Second Life in a former real life) and Ian's healthy dose of cynicism is worth a read. He's covered Heineken's presentation on why not to go into Second Life.
If you're trying to set out a case for why a brand should engage in some kind of social media activity, you need to fully understand the case against. Only by being able to fully explore why someone would say no a campaign, are you going to able to confidently hold down a discussion on the topic. Nice post Ian.