Web sites that accept postings from the public, like this wiki, are often abused by spammers who use automated tools to post links to commercial sites. While these spam links can be removed, they are a significant nuisance.
To prevent automated tools from making changes to this site, this wiki presents users a simple math problem and asks them to answer it when editing a page or creating an account. Though it wouldn't be hard for a spammer to automate this task, so far this simple requirement has greatly reduced spammers and other robotic attackers. One advantage this simple method has over more complicated similar tools (that often rely on distorted words) is that users with limited vision or using text-based or speech-based browsers should not have a problem with the math problem.
If for any reason this tool is unexpectedly preventing you from making legitimate posts, please leave a message at the site admin's talk page.
Hit the 'back' button in your browser to return to the page editor.
April 2007 update: Recently an automated tool has been used to delete content from random pages. Previously only anonymous edits with new external links (possible spam) were required to answer math problems. Going forward our math captcha will be required for all edits by any users that isn't logged in with an account with a verified e-mail address. Sorry for the inconvenience. (Users are still welcome to post anonymously--they just have to answer the math question.)