If you're wondering who to target in your marketing campaigns then a useful barometer is one of the recent Forrester Research charts on consumer trust. Check out this new blog post from Forrester's analyst Jeremiah Owyang who republishes some good graphs which I've seen around before in various guises. Useful nonetheless.
The consensus? We trust bloggers very little, but peers more than the media. The paradox I think though is that surely these two camps can often be one and the same.