I resisted doing this for the longest time, but, well - it's just really not possible to have a publicly accessible website and not protect it with CAPTCHAs.
So now CAPTCHAs are required for creating accounts and posting comments.
I hope you're happy, spammers.
And not terribly surprisingly...
I'm still getting spam comments. Not sure it actually reduced the number of spam comments, really. Or number of spam user accounts, either.
Oh well. At least I only get like five junk comments a day. I'd hate to run a bigger site.