Comment on Reviewing The Growmap Anti SpamBot Plugin (G.A.S.P.) Update by dellauk.
There are plenty of anti-spam plugins that bloggers can use to try and prevent the posting of comment spam. These vary in effectiveness, and amount of administration involved in ensuring that genuine posts are not categorised as spam or vice versa.
If you can prevent the majority of spammers from targeting your site in the first place, then you will reduce time spent on moderation and the chances of letting spam through.