WSUS is one of the first Microsoft products that has
a wiki site. The wiki site has been growing rapidly since beta 2 of WSUS; It is getting about 2000 hits a day at the moments.
I looked around at several wiki engines and wiki farms before settling on editme.com as the host for this wiki. My key requirement was a WYSIWYG editor and back in October only Editme had a decent wiki engine and simple to use editor. I really like JotSpot.com user interface but sine they are not yet out of Beta and require users to pay a fee to view the content I couldn't use them.
I have been relatively happy with editme. The editor has several bugs but in general it is stable.
Fortunately so far we have not had to deal with wiki spam and vandalism. Hopefully it will stay that way even with more publicity for the product and wiki.