I noticed he'd been spamming our comments by putting up ads for his site. It's fine to link to a post on your site if it's related to something on-topic in your comment; it's even fine if the link is part of your signature; but cluttering our site up with unrelated ads for your site is not fine, and it's usually pretty easy to tell the difference — it surely was here.
A google search reveals that he's also been doing the same on other blogs. I've banned his IP address from our site, and I wanted to alert other bloggers, in case they want to do the same.
UPDATE: The Hollywood Liberal e-mailed me in response:
Sorry, didn't know that was a problem. I don't want to cause any trouble for you, or your site, which I really like I'll stay off of it from now on.I appreciate the apology; I would have thought that it was pretty obvious that spamming people's comment threads wasn't quite proper, but I'm glad to know at least that the cause for the spam was ignorance of the norms rather than deliberate disregard of the norms.