We’ve found that most wikispamers — like their email spam cousins — aren’t especially imaginative. They’re most often injecting links into pages in patterns that are significantly different from human editors. Thanks to some content analysis systems borrowed from the email spam world, we can nail these edits almost 100% of the time, or require a captcha in edge cases. Unlike email, we’ve also got existing page content to compare to, so we can scrutinize only the diffs. We’re using these techniques in real-time to nail spammers, and they’ve worked very well across millions of pages of content. I’d be surprised if most wiki hosting providers aren’t doing the same.

James from Wikispaces