(If we have more spam, I can promote a few users to admin status to ban spammers faster, but so far we have had only one case.)
Unfortunately the situation with the X-Plane SDK Wiki is not as good. The problem is that the SDK Wiki does not use MediaWiki - it uses phpwiki, so we do not have the rich set of user admin tools that MediaWiki comes with out of the box. There is currently a user who is (for some reason) attacking the user database by registering fake email addresses over and over. I do not know what the user hopes to accomplish, other than wasting my time.
The unfortunate side effect is to leave the SDK Wiki user database in a state of chaos. When I have time, I will be adding some new features to the user signup code and trying to clean out the user base.
Why are we not using MediaWiki for the SDK? Well, besides history (we used what we found at the time), the SDK Wiki's code is customized to integrate the SDK development tools with the Wiki itself. This is how you get the latest documentation and user generated content on one page when you look up an XPLM function.
There is no scenery system Wiki - something I have debated a bit. At this point though I am more concerned with getting the scenery tools out than with updating the documentation; once we have a more complete tool set, then I can ask the question "can users figure out how to use these tools."