Systems and methods for managing data associated with incoming electronic messages including filtering incoming electronic messages according to the sender's address. In addition, a request/response technique categorizes sender's addresses as authorized, unauthorized, or unconfirmed, which categorizations are stored in associated data structure. The filtering processes and the categorization techniques can be used in connection with any of various methods for populating the data structures that identify sender's addresses associated with authorized and unauthorized senders. In this manner, recipients can effectively cause unsolicited electronic messages to be filtered out. Moreover, the processes generally do not require the recipient to view electronic messages and make decisions regarding whether the senders are to be categorized as unauthorized; rather, the timeliness and accuracy of the senders' responses determine whether specified senders are authorized or unauthorized.