This paper describes two innovative analysis methods for IPv4 address sets such as antispam blacklists. First, the contents analysis provides means of measuring key properties of any set of IPv4 addresses as well as revealing relationships between such sets. Second, the behavior analysis defines behavioral attributes of querying addresses and requested addresses. Furthermore, the behavior analysis provides an insight into the global email communication. These two analysis methods are applied and the empirical results are presented as part of this paper.