I have started a few wikis (using Mediawiki, and kept up to date) and I have found that we are being spammed, about once every ten days. Usually links to drug (pharmaceuticals) sales sites in hidden text. These wikis are very low traffic but are linked from Metawiki at:
http://meta.wikimedia.org/wiki/Sites_using_MediaWiki
I have also noticed a wiki that has been set up and the WikiSysop has no idea how to actually build content in the site. So, what does he get? Spam! No content, nothing. Just spam.
It would seem WikiSysops should be made aware of their responsibilities, when Mediawiki software is installed. Should theyt have to pass a test? It is great that installation is so easy, but that lowers the threshold of a potential WikiSysop admin to be verging on the almost clueless.
Another effect. Users are registering email in the domains that I own, in which the Mediaiki wikis live. Hence, I see all the email confirmation emails (to addresses such as anythinggoes1234 @ mylittlehouse.org.uk). This is a relatively new feature, suggesting again increasingly clueless spammers are getting in on the act, perhaps?
Is there a message here?