Here's another alternative:
This idea is based on the fact that the poker spammer dumps comments in for posts that may or may not exist.
macmanx - I disagree with your assertion that " The only way to stop SPAM is to turn off your comments." That simply isn't true. As I said in a different thread, if some one is determined enough, they will get through. What you can do is to make is so difficult for them that they don't bother. Between all of the items I have in place (the above hack, as well as BlackList - which I need to update) I've been reasonably secure from spam. Now, I have to admit, I don't know if it's because I haven't been targeted, or if my security is adequate. Turning off comments just doesn't cut it. That's the point of blogging (for me at any rate) is to get feed back from my readers (as few as they are.) Honestly, there are a number of blogs I've stopped visiting because I couldn't comment on their site. Sure, I could post the comment on my site and link back to them, but 1) It takes the comment out of context and 2) My site has a focus, and I try not to clutter it with non-related items.