Since I moved from Movable Type to Wordpress just over five months ago, I have been using Akismet for dealing with comment spam. So far, my experience has been great.
Since then, Akismet caught over 17,000 spam comments, i.e. about 130 per day. During this time, there were just 24 false positives and 1 false negative. Very impressive.

{ 2 comments… read them below or add one }
Akismet is excellent, it found 262.788 spam comments on my blog,
I wondered for quite some time if I need a CAPTCHA, but Akismet is good enough for now.
Peace
Stephan
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Programming is hard – http://blog.codemonkeyism.com
http://twitter.com/codemonkeyism
Sometimes it’s really that simple, isn’t it? I feel a little stupid for not thinking of this myself/earlier, though.