Our high-tech anti-bot captcha
IMPORTANT: Before creating your account, please read this note all the way to the end. If you don't, you won't succeed in creating the account. Sorry for the extra step, but it has proven successful in eliminating "bot-spam".
NOTE: after doing the trick, you might end up with a negative number. For example, let's say the problem displayed is "9+3". The answer to that is "12". But "12-42" is negative, and we've had at least one user who had trouble with that. Here's what you do: swap the two numbers around so that you have "42-12". The answer is to *that* is "30". Now put a minus sign in front. "12-42" is "-30".
WHY SO HARD?
I know adding this trick seems a bit ... unwelcoming. And annoying. The admins feel bad about that.
But if we seem paranoid, be aware that this WIKI is actually our second try. The first try didn't have an enhanced captcha, and within less than a week, there were over a hundred "bot" accounts entering spam. There must be automated scanners out there looking for WIKIs (and message boards and etc) with simple account creation flows.
Unfortunately, the admins have day jobs and get very busy, so we can't really monitor the wiki and remove spam as it appears. So we had to make it harder to get in.
Finally, I tried to add a link to this page from the account creation page. But the account creation page is one of the few pages which is NOT stored as an editable page. It is generated on the fly by the code itself. I could change the code, but that is both difficult and complicates the process of upgrading to a new code version. Plus, there is a class of semi-automated spam bots where low-paid humans (possibly slave labor) respond to captchas all day long. Adding a link to this page from the account creation page could defeat the purpose of the trick.