This Seattle Post article gives a nice balanced view to both sides the concerns of the company as well as to the employees blogging.
I especially like this quote: "Microsoft is like an anthill, and I'm an ant," explained Scoble, the employee who always thinks about justifying his posts to CEO Ballmer. "I'm allowed to give the ant's perspective on the world, but I'm not allowed to give the anthill's perspective on the world."
Replace Microsoft with SAP and Ballmer with your favorite board member and you have a pretty good guidance on what should be posted here.
