It appears from my sources in the States (Ok a bunch of PR folks I know on a mailing list!) that some unsuspecting bloggers are about to be targeted by PRs. MediaMap (a commerical database of media contacts) has started to include blogs by journalists.
There are so many poor (as in not very good, rather than no money) PR people out there that this could seriously backfire on some. These mugs will think all they need to know as add that journo on to the end of a news release distribution list and away you go. My guess is that you'll see some bloggers slagging off thier clients as a direct result of such a crass approach.
That's not to say that I don't think PRs should target blogs. We definitely should. Word of mouth is the most powerful weapon in the martketing armoury. Some of the more popular bloggers are powerful opinion formers that you will want to influence on behalf of clients. But just like targeting Usenet/newsgroups you have to be subtle. You have to play the game by the rules and make a real effort to take part rather than just try to crudely peddle your own agenda.