Rosalind - 3:09 pm on Jan 11, 2011 (gmt 0)
So far I don't have any problems with bots. However I guess this only works because nobody else is using this solution.
I'm inclined to agree, and I think that's always going to be the problem. For most websites, a mass solution is what's going to be used: either a solution for a single website with a large audience, or something that the vast majority of non-technical webmasters are going to want to adopt.
I haven't had trouble with bots for years, since I implemented my system. It's only slightly unusual. Once you make the effort to create something that other people aren't using you're no longer worth the spammers' time to crack. But people are fundamentally lazy, so we'll never reach an ideal situation where all webmasters use a slightly different bot-beating system that they've thought up themselves.