I've had this problem on my wikis. One solution is to put passwords on them. When I have a wiki for a class, I usually make one password for the whole class, and it is usually something like "password" or the name of the class. For other wikis, we have a spam filter. We have a database of banned domains, and if you try to write a page that contains a URL for a banned domain, the wiki pretends to accept the write but actually throws it away. This, coupled with the ability to go back to a previous version of a page, keeps the spam to a minimum. I've done this for WikiWorks and swiki, but not for Pier. -Ralph Johnson