A request to send messages is received by a sender messaging service from a sender. The messages are for one or more recipients associated with one or more recipient messaging services. The sender messaging service can determine that at least one of the plurality of messages is indicative of message abuse. The sender messaging service can generate a warning message which includes at least one of an indication of the sender, an indication of an address of the sender, and an indication of the message abuse. The sender messaging service can send the warning message to the one or more recipient messaging services.