I’ve activated it. If it works, spam comments will be blocked while comments flagged as possible spam will require commenters to perform a “copy the image” action to prove they aren’t spambots. This should be an improvement over the current system, which puts all suspicious-but-legitimate comments into the general spam queue where they are almost impossible for me to find. Please email me at the support address if you have problems. I need your feedback to determine if this system works as advertised, so please try to leave comments on this post and let me know if your comment either disappears or you get prompted to copy an image before your comment posts. Thanks.