Comment spammers get their revenge

It seems there is a new technique for comment spammers to get their revenge on those of us running mt-blacklist - spamvertise non-existent sites. Use compromised computers all over the world to create entries with random character urls, so that no two comments are the same, and therefore impossible to de-spam with mt-blacklist. All you can do is delete them manually one at a time >:( And of course the only way to stop an attack is to rename your mt-comments.cgi to something else.

I can see no point in spammers doing this, other than pissing off bloggers that have mt-blacklist installed blocking their sites.