Speed up Mail.app
 Thanks to hawkwings.net for pointing out this great tip. I’m sure you don’t care how it works just that it does but incase you do, here’s the original post.
1. Quit Mail.
2. Open Terminal.
3. Type the following:
cd ~/Library/Mail
sqlite3 Envelope\ Index
An sqlite> prompt will appear.
At that prompt, type vacuum subjects;.
After a short delay, the prompt will return. Type Control-D to exit.
4. Restart Mail and enjoy the extra speed.
May 14th, 2008 at 9:24 pm
Very useful information was found here, thank you for your work.