Ounce of prevention: Adam Kalsey is in a war against comment spam, and he shares some great ideas here:
“What will probably be the biggest help is the thing that was easiest to do: changing the comment script name.
What else would be effective is changing the names of all the form fields. Making them short random strings would make it impossible for a bot to recognize the comment form using only the field names. People would be able to understand the form because of the labels, but bots would have to implement a large amount of fuzzy logic in order to recognize that ‘Name,’ ‘Your Name:,’ and other forms are really the same thing.”