There’s a bewildering statement in Paul Noble and Tom Watson’s otherwise sound book on Evaluating Public Relations. They state that ‘the monitoring of online public relations is one of the black holes in the evaluation lexicon’.
If they mean that it’s murky and unclear, then they may have a point. If they mean it’s pure guesswork, then they’re simply wrong. Here’s an excellent discussion of blog measurement metrics from Stephen Davies. (He’s spurred me to start exploring Feedburner; and has indeed added some words to my lexicon.) And here’s a more holistic view of blogging benefits from Kami Huyse.
UPDATE: Here’s proof that it’s still a murky business. A new blogger confesses she’s even more confused than me by all these new tools.
PR Studies 
I’ve had a message from Traci at Feedburner explaining what it does. Unfortunately, the spare tyre is here to stay…
I tend to agree with Heather. I’m trying to discover what exactly all this technology will do for me blog and i’m supposedly one of the ‘tech-savvy’ types.
Feedburner is a great tool, you can track what people care about, which I find is often my delicious links — yet another service I have found invaluable.