Just thought I would let you know about a cool blog (if you are a sysadmin or webhead, such as myself)
Ann Elisabeth’s blog contains a lot of information about various referrer, trackback and comment spammers. She has gotten really good at digging them out from their hiding places and finding all the sneaky ways they go about their business.
If you are a sysadmin you will really love her blog. Go read it now.
Thanks for the plug.
Even better, check your machines for signs of being an open proxy. Signs of that are:
1) Bandwidth has steadily increased, and the machine is getting slower.
2) You find lots of hits in the logs from banners and blogs.
Make sure your logs include referrers and user agents. That can help you figure it out.