We used to receive thousands of spams in our comment section, but installing one simple plug-in made them all go away. Even we were surprised by the success of the new module.
Finally we figured out why it worked so well, thanks to Titus Brown. As it turns out, the math problem in our comment section was configured as 4+1=3, which not only confused spammers but also likely drove mathematically skilled bioinformaticians crazy.
Sorry folks, there was nothing fancy. It was only a mistake in configuration.