Until now, I’ve required users to be registered on the blog in order to leave comments. I’ve realized however that this does act as a deterrent to people who would impulsively comment but don’t want to load a few extra screens. So, I have taken a cue from Shamus and installed a captcha plugin. I’m using a derivative of the one he uses, called Peter’s Math Anti-Spam Plugin, and again taking a cue from Shamus I’ve configured it so it shows exactly the same math problem every time. (Incidentally, please assume completeness of the Real numbers before answering. Thank you.)
If you are a registered user, and are logged in (use the handy login form on top of sidebar) you won’t ever see the captcha. I am still disabling all pingbacks and trackbacks, and have also installed a domain blacklist to prevent spammy email addresses from registering (mostly mail.ru. Sorry, Russian Haibane fans). And I’ve got Akismet purring along in the background. Spam hasn’t really been a problem until now and if this (marginally) more open scheme results in a big increase in spam from registered bots, then I’ll yank it.