A lightweight POP user base typically consists of residential dial-up users with simple messaging requirements. Each concurrent client connection sends approximately four messages per hour. These users read and delete all of their messages within a single login session. In addition, these users compose and send few messages of their own with just single recipients. Approximately 80 percent of messages are 5 Kbytes or smaller in size, and about 20 percent of messages are 10 Kbytes or larger.