Last Friday I decided that enough was enough in terms of the amount of comment spam I was moderating, so I installed the Akismet plugin for WordPress. I’ve always held off doing this, because of the requirement to sign up to yet another 3rd party service (in this case wordpress.com), even if it’s only a “basic” membership and free. However, given that it’s already pre-moderated over 1000 spams since installation, I think it was probably worth it 
If you feel your comment may have been accidentally marked as spam, then drop me an email.
mrBen
I was just thinking about how Akismet has become far less effective, for my two sites, than it was when I first installed it. It is an improvement on nothing, though
I’ve found Spam Karma to be excellent since I installed it – I chose it over Akismet mainly because I didn’t want to sign up for WordPress.com.
Akismet has served me well; it lets very few spam comments through, and on my site, I think I have yet to see a false positive.
That, and in the last year it’s blocked over 17 thousand spam comments… I don’t even want to think about deleting that many comments by hand…