I am running MediaWiki 1.5.1 on
www.drumcorpswiki.com
and over the
last two weeks or so, I've begun having major spam problems.
I suggest to install the SpamBlacklist Extension, together with the
regexp mentioned by Paul or
$wgSpamRegex="/<div/";
if div is an element that your users would not enter.
I have lots of spambots attacks each day, but none get through :-)
Patrick