dive into mark:Club vs. Lojack solutions
This is a great read. Mark has a way of using (or at least pointing out) some wonderful analogies.
I haven't been hit by the spammed comments, however, I have been gotten by the spam referrers (I think). I get a good number of referrers, but very few comments, which may be the reason.
Mark is a big fan of conversation on the web, and comments are a good way to drive that, however, the people he "converses" with mostly do so by posting on their own blogs, creating things he can see. However, what if you don't have your own blog, but still want to be part of his conversation? You could try email, but that might not be very permanent, which is something Mark likes. Comments on a blog, for me, are just like posts, and if done correctly (ie, look elsewhere because I haven't gotten that far yet) can even be permalinked, just like a post, with anchor tags and all.
I don't know what I'm trying to say here besides the fact that I personally feel like comment systems are a big part some web communities, and are a necessary and important part. I'd hate to see the spammers get them. Maybe the lo-jack solution for this is some legal action: place some really blatant warnings about what can and can't be posted in your comments, wait for a spammer, and then nail them in court as loudly and publicly as you can. This isn't a good solution for those of us who can't afford it, but might set a lo-jack like precedent. Some people have already won on the spam front (such as the guy who got nailed for faxing people junk). Might work here as well.