"I've mentioned before my love for Thunderbird. Through its
support for the POP3 and IMAP4 protocols, the program is compatible
with nearly any messaging system, and its cross-platform nature
makes it ideal for mixed-client environments. Like any love affair,
though, ours has not been without its complications. I discovered
that Thunderbird's Profiles directory could get really large, even
when it seemed that it wasn't storing that many messages. After
some investigation, I've found that the developers have built in a
facility for keeping the program's disk consumption under control,
and that's the 'Compact Folders' command..."