A system of ranking e-mail threads is disclosed. The system receives e-mail messages, and determines e-mail threads in response to the e-mail messages. The system determines an e-mail rank associated with each e-mail message in the e-mail threads, where an e-mail rank associated with an e-mail message is determined in response to a sender identifier related to the e-mail message. The system also determines a thread rank for each e-mail thread, where a thread rank associated with an e-mail thread is determined in response to e-mail ranks of each e-mail message associated with each respective e-mail thread. The system then determines an ordering of the e-mail threads based on the thread rank associated with each e-mail thread.