Overnight, the SpamCatcher plugin on my Movable Type installation failed rather spectacularly, allowing some thirty spams to pass and get published without even getting flagged. Half of these were gibberish comments, which are very difficult to filter, but the other half were "Good site! Thanks, have some spam" comments, which the regular expression filter should have caught, but didn’t. In other words, under conditions which apply to a small blog that only a handful of people post comments to, SpamCatcher can not be relied on to work properly. Bit of a disappointment, that.
Cleaning up spam takes a lot of time, especially because another misfeature of Movable Type is its resource hogging. Every rebuild of a post here comes close to hitting the resource limits Xepher.net imposed after a spam attack on this very MT installation took down the entire server two years ago. Mass rebuilds such as those I carry out after a spam cleanup hit those limits, causing the process to time out, so that the spam stays on the published site.
I really don’t want to close comments, so instead I’ll gradually escalate my spam defenses. Step one is raising the junk filter threshold, so that more things will get junked based on the probability of them being spam. This will not reduce the time spent looking over the comments in the backend, as I’ll have to fish legitimate comments out of the junk folder, but it will cut down on mass rebuilds. It also won’t make the regex-based filtering functional, but it should at least get me rid of the gibberish.
If it doesn’t work well enough, I may hold all comments for moderation, or go to authenticated commenters only. Or as a last resort, I may switch off commenting again until an anti-spam system that works can be installed.
I’m even open to switching blog software, though this will also lead to me having to do work that I Really Don’t Want To Do. I’m unimpressed with WordPress, because it’s a single-blog system that you need to arm-twist and wrangle into doing multi-blogging, but there may be other systems that do what I want a blogging application to do.