Looks like some people are posting like crazy new articles on the wiki... does appear to be affecting the existing pages that i've seen:

http://wiki.quakeworld.nu/Special:Recentchanges

http://wiki.quakeworld.nu/Locating_great_Quality_central_Heating_Supplies_online

Yea, thats spam.

I cleaned it up dozens of times, me and Purity afaik.
I've told the authorities (aka Zalon) but nothing was done yet. Johnny_cz suggested some solutions (including a captcha on new user signup - dahh) but nothing was done.
I got tired, the spam is so much, the cleanup took more than 30 minutes every 10 days or so. So i stopped doing it. it was donkey's work, i had enough of it.

Close new user registration.

Done.