The spam in the wiki, which I have been browsing through lately, is so annoying that I have decided to use some of my time to revert the affected articles that I come across.
[ptoki] I did this as well in June. Its hopeless. There are a couple of options: Make editing harder (any kind of captcha while logging in) - easy to override. Lock and forbid editing after cleaning up - not nice. Alert admin on oesf forums. (I will do this). Make a mirror of this knowledge and abandon this junk.... :(