Mailmgr is a Sendmail Analisys Report Generator.
The html reports contain the following informations:
Username
messages sent
messages received
bytes sent
bytes received
Messages from with date, time and bytes per user
Messages to with date, time and bytes per user
WWW: http://sarg.sourceforge.net/
ref. http://home.so-net.net.tw/weithenn/freebsd_mailmgr.htm