Hi all... I'm a bit sheepish about this but I just wanted to draw some attention (hopefully the good kind) to my first public WordPress plugin, RegisTrap.
It's extremely basic, but that's the whole point. With all due respect to the developer of SABRE, I tried that for a while on my site, but its myriad spam blocking techniques were overkill for me, and worst of all it seems to have been preventing legitimate registered users from logging in. (Not sure if I just had it configured wrong or something, but as soon as I disabled it, the problem was resolved.)
I wanted something that would be completely unobtrusive, with no visible changes to the registration form for human users, so I set up this plugin. It uses some simple bot trapping techniques to do the job, and so far after running it for over a week on my site (i.e. long enough to know for sure it's working) I haven't had a single spam registration.
It's just version 0.3 right now. I welcome suggestions for improvements and certainly want to know if anyone finds bugs or worse yet that it just doesn't do what it's supposed to. I suspect, especially if it becomes popular and well-known, that its bot defeating techniques will start to fail, and if so I plan to counter that with a basic admin page to allow site-specific customizations. But right now it works great and requires no configuration whatsoever!
If you've been looking for a reliable and, above all, SIMPLE solution to registration spam, please check it out. Thanks!