This is a plugin for the ConfirmEdit MediaWiki extension. ConfirmEdit gives us the additional addurl permission that MediaWiki doesn't have. I set this addurl permission to require a captcha and then wrote this captcha plugin for the ConfirmEdit extension.
The gist of it is that it always rejects changes that add urls with a nice message if the user isn't in the emailconfirmed group.
I wrote this while working at PCF. Initially it worked super duper, but later I think it worked less well.
Regardless, I'm moving it from the original repository to github where it's less likely to disappear.
The name is ridiculous---I know. But it is what it is.
If you have issues, create a new issue in the issue tracker at https://github.com/willkg/ecnc/issues.
Pull requests would be super duper.
Announcement blog post: http://bluesock.org/~willg/blog/miro/spam_reduction