I was going to suggest this several weeks ago when someone posted a spam response to one of your mystery language quizzes, but now that the comment total for this week's quiz has suddenly leapt to 55, I doubt you need much convincing! (rueful smile)

I don't know what your software provides in the way of spam filtering, but Wikipedia discusses some possibilities here:

http://en.wikipedia.org/wiki/Spam_in_blogs

I noticed a clever trick on Macworld blog today, where they ask you a question with an obvious answer, and you have to type in that answer. (This is one of the possibilities mentioned on the Wikipedia page.)

Good luck!

Wow. In fact all posts from 13 to 65 are spam!

http://www.omniglot.com/blog/?p=1981#comments

Curiously all the domains the posts link to are from China.

I've just installed a plugin that should stop most of the spam on the blog.

It's doubtful they are actually FROM China. Many spammers use a network of insecure mail servers that are scattered across the globe. The spammer may have been some kid from Scranton who lives in his mom's basement and has a couple of spambots. The logs can show you the site and port of origin.

That's why I said "the domains", not the spammers.