Antispam Service
When talking about antispam service ( service that willl identify spam from comments thats submit to your blog) , most of the people might only think about akismet because of wordpress , in fact there are 2 other service that i found when i doing research recently
take a look download page on Defensio , you can see it support different type of blogging engine, movable type which is using perl , Mephisto which is using ruby on rails and it also support habari , a very new blogging engine.
For Mollom , althought their download page might not as impressive as Defensio, but it support 3 of the major engine, which is drupal , worpdress and joomla, my dev blog currently is using Mollom when i get fedup for using akismet on drupal, so far it serve me well, none of the spam get through yet.
Just list out this 2 other choice if you are using wordpress or maybe you wish to use a self host anti spam like spam karma which just gpled.