Wiki spam has become very common and the spammers are using more and more advanced techniques. It is now common that spammers use automated bots to edit many pages automatically. They also often have access to many different proxies and different IP addresses. This makes it increasingly difficult to fight spam. Due to the advanced spam techniques used by the spammers spam control often needs to be done by an administrator.
Here is a small check-list on what administrators should do when they find spam in the Wiki:
First block the offending user. This is most easily done by clicking the "block" link in the Recent changes list. Use an infinite expiry time. Blocking of a specific user or IP address or address range can also be done on the Special:Blockip page.