This is not a typical SPAM IP blacklist. ZeuS is a malware/bot that is used to steal credentials for online services. This RBL lists the ZeuS Command&Control servers (C&C) and malicious hosts which are hosting ZeuS.
Is the information on our site wrong or incomplete? You don't want us to monitor your blacklist? Or do you operate a similar blacklist? We would like to hear from you!
We keep some statistics on blacklists. Below is the graph for ipbl.zeustracker.abuse.ch. We test blacklists by asking them to respond to known IP's that are blacklisted and known IP's that can't be blacklisted. Not every blacklist has such IP's, we test them with what is possible. We keep if we get any response or error messages and the response duration. Lower response times are better. These statistics may be useful for email server administrators to pick which blacklist to use.