Please don't vandalise our fair wiki. Thank you.
For obvious vandals who mass-delete pages or perform other malicious behavior it is possible to rollback all edits by that user. It does require the rollbacker permission to be given to a user. To see the list of all current users with said permission, see: Special:Listusers/rollbacker.
If you want to help fight vandalism, apply to receive the rollbacker permission and fight wiki spam!
For proper use of the tool, see the wikipedia help article: 
We primarily have persistent nonsense-string vandals; the occasional wiki-troll who signs up with an annoying name; and one or two page blankers.
An analysis of the block logs (as a surrogate measure for vandal activity) is linked off of this page OLPC:Bot_Interest_Group. The hope is to get some people intersted in adapting some of the fine countervandalism work that has been done on other MediaWiki installations. Unfortunately, the analysis suggests that vandalism is a problem that has begun to get worse in significant ways and that some automated means will be required to defend the wiki.
Tools we should add
- Auto-unblanker : revert page blanking and other dramatic changes, when done by new or anon users
- Auto-signature : sign non-minor page additions made by anons with their IP (existing script)
- Instructions for rc-watching tools (cf wikihow and wikipedia tools)
We need a set of "please don't vandalize" templates, for contribs who are actively involved (and not just bots), but vandalizing; it's sometimes better to warn and encourage people to become contributors than to block on sight... and easier to do this when there's a template handy. Without checking wp templates (which are a bit more involved), I started substing Template:nov. --Sj talk 10:11, 24 April 2008 (EDT)