The Spamhaus Exploits Block List (XBL) is a realtime database of IP addresses of hijacked PCs infected by illegal 3rd party exploits, including open proxies (HTTP, socks, AnalogX, wingate, etc), worms/viruses with built-in spam engines, and other types of trojan-horse exploits.

There is a trackback validator plugin which checks if the IP address of the trackbacking server is the same as the URL it is trackbacking for.

Every time I have to find the Google Analytics tracking code again for an existing website (rather profile) , I go through the same pain of hunting it down as it is definitely not obvious.