Strange Message

[Michael Abraham Shulman <shulman@caltech.edu>]

Every so often when logged into the console, I get a message looking
like this:

PAM_unix[28529]: (cron) session opened for user mail by (uid=0)

Can anyone tell me what this means?  Is it a problem, and if so, what
can I do about it?

\\// | R | T R | L B | //\\ ~ Michael Abraham Shulman
mailto:shulman@caltech.edu  ~ jabber://mas@jabber.org
http://kurukshetra.cjb.net/ ~ GnuPG Public Key #21A279E5

People who fight fire with fire usually end up with ashes.
        -- Abigail Van Buren