Jay Allen gets my vote for supreme arbiter of goodness for this page which documents installing a variety of plug-ins and templates inside Movable Type to block the display of comments which contain URLs repugnant to you. It's not a complete solution, but it does mean that the idiots and scum who have started to spam the comments section of Movable Type (and other) blogs can be suppressed.It's based on looking for domain names and URLs in the posts and author info in comments, which means that you get the spammers where they leave. They can circumvent all kinds of content restrictions, but in comment spam, they have to link you somewhere. This shows off the power of Movable Type's extensible architecture. Hooking in Jay's mods took a few minutes. I just had to install a few simple plug-ins, copy his template, and add a bit of If..Then code into the comment templates, and voila!