Systems and methods for delivering solicited electronic messages to a client. Senders of electronic messages become authorized senders and electronic messages from the authorized senders are delivered to the intended recipients. Electronic messages from unauthorized senders are not delivered. A sender becomes authorized when a user includes a tracker in the user address that is associated with a particular sender. Electronic messages that include the tracker are only delivered if the sender is the same sender that is associated with the tracker provided by the user. Senders are also authorized by detecting when the user provides a user address to a sender. Users are given the opportunity to opt-in to receiving electronic messages from senders that have registered with the electronic messaging service that provides electronic message services to the users. Authorizing senders in this manner permits the delivery of solicited messages while rejecting unsolicited messages.