Matt Hovey, the developer of an amazing email format conversion application called Emailchemy 
has written a nice piece explaining why was driven to create the app.
Hawk Wings has covered Emailchemy before.
It can convert emails and mailboxes from an astonishing number of email clients (AOL for Windows, Claris Emailer, CompuServe Classic for Macintosh, CompuServe 2000 for Windows, Entourage (Database, .rge Archives and cache files), Eudora, Mail.app, Mozilla, Mulberry, Musashi, Neoplanet, Netscape, Opera, Outlook for Windows, Outlook Express for Macintosh, Windows and UNIX/Solaris, PowerTalk/AOCE for Macintosh, QuickMail Pro for Macintosh and Windows, Thunderbird, Yahoo! Mail and any other UNIX-style or mbox-format mailbox—whew!) into “mbox” format, mail spool, or “UNIX-style” mailboxes, folders of individual email files (.txt or .eml files), comma-separated value files (.csv files), IMAPdir (Binc IMAP maildir) or Maildir++ (Courier IMAP maildir) format, or IMAP formats usable by Outlook, Outlook Express, Entourage, Mail.app, and Thunderbird.
Matt recounts how he moved from his beginnings in mail on UNIX (in 1990, when I was still fooling around on a PC with Waffle, Fidonet and UUCP email) through a dizzying sequence of email clients mandated by “corporate policy” at work and the march of software progress at home:
I went from using Eudora at work to using Apple’s PowerTalk, and from that to using WordPerfect Office (aka Groupwise), Microsoft Exchange, Lotus Notes, and finally Microsoft Outlook. Then, to further complicate matters, I went from using Eudora at home to using Apple’s PowerTalk, Claris Emailer, and Netscape Mail, back to Eudora again, and then finally Apple’s Mail.app that came with Mac OS X.
It’s all very nostalgic! No wonder he ended up with “years of archived email saved in files created by several different applications that no other application could read.”
That’s enough to convert anyone into an ardent disciple of open formats.
If you are in the same bind, Emailchemy (shareware — USD 29.50) may well be the tool for you.
