Originally Posted by Forkbeard

If you have a blog where you need comments open and you're fighting high volumes of comment spam robots, you may find this useful:

NoSpamNX

There are a ton of different anti-comment-spam approaches and this one is not the sole solution, but it does cut down volume enormously. I have a blog where this plugin alone has blocked half a million spam comments since August of 2010 when I installed it.