Google has a plan to completely remove the incentive for their evil trade. That’ll teach the bastards.
Things have been more relaxed around here since I wrote an sql script to auto-disable comments on posts older than 30 days. Before that I was ending up with so many comments landing in my moderation queue that I didn’t even have time to read them all.
When things were at their worst I was tempted to follow Tom’s example and add an image to my comment form, but I decided against it. By necessity that approach is completely inaccessible to blind users, and if anyone noticed my hypocrisy the only honorable way out would be seppuku.