Tim Bray is looking to add comments to his blog, and posted a set of ideas he's ruminating on. Sam Ruby responded with some himself, and I have to say, I'd echo what he's said about comment spam prevention:

• Use an IP Throttle
• Use a simple filter

The filter I added to our Wiki the other day is working out really well. For some reason, spam comes in waves - I get a ton of the same stuff for awhile, and then it quiets down - only to roar up again later. The IP throttle and filter stopped that stuff pretty well. For this blog, I use an additional technique: I toss any comment that has "too many" hrefs, on the assumption that most commenters are not adding tons of such references. That stops the massive porn/poker/pharma link spam that floats in.

Like Sam, I've decided against moderation - it sounds too much like work, and I really don't want the blog to become that kind of chore. Thus far, the only thing I've had to turn off is trackbacks, and I intend to push the filter code from the Wiki codebase over to the blog so I can turn those back on.