Baseline has an article on Robert Scoble who is a member of the Windows marketing team and a blogger:

The blog, which Scoble established before hiring on with Microsoft, comes off like a conversation with a smart friend. He links to other bloggers, makes recommendations about Windows-related products, talks about his own upcoming demo of the next version of Windows, known as Longhorn, and mentions the need to balance his personal and professional lives. Almost anything is fair game. "That is the first Apple marketing in a long time that makes me want to buy an Apple product," he wrote recently about an ad for the iPod music player.

And...

There are some barriers to adoption. Using weblogs means trusting your employees to speak honestly and openly. It means conversing with customers, not just marketing to them. It means even more flattening of your organization.