For some time I’ve had problems with spam commenters. I’ve held them at bay mostly by having an extensive spam word blacklist as well as holding all comments with even one link in the approval queue. My blog had been somewhat dormant for the last year, and I guess the spam bots had been lying in wait or something because soon after I started posting again, my database had been filled to the brim with spam in my approval queue, to the point where my host turned off write access!
I looked at various spam deterrants for blogs and found Akismet. It’s not just a blog plug-in, it’s a whole service which continually monitors comments and posts to many different blogs and other sites which accept user contributions. Using this massive amount of data it can quickly learn how to filter out spam, even as spammers come up with new tactics.
Akismet is free for small blogs, though they do ask if you’re making tons of money to use their pay service. Overall it’s a great service for the average blogger. Unfortunately it’s not without its downsides. You do have to send every comment through their servers and you have to trust that they don’t throw out any good comments. I don’t have enough user discussion to test the false positives, but so far I’ve not had any problems.
I installed Akismet on August 11th, and already it’s stopped over seven thousand spam comments from being made on my blog alone! Here is a live counter of spams stopped since August 11th: