NBC anchor Brian Williams is traveling with the president today and has blogged seven posts--and counting. Read the blog, though, and you can see the constraints Williams works under. Other bloggers would be able to give us impressions of the president--tell us if he seems confident, well-prepared, if he's making good sense. Williams limits himself to describing what it feels like to be traveling in the president's entourage. These are blog posts written to ruffle as few feathers as possible.
All mainstream bloggers face certain limits. But I think network TV anchors deal with far more, as they blog, than the rest of us.