Boot slowed by "MTA: exim4"
 

When I boot my computer, it hangs for about a minute at a line that says, "MTA: exim4". I checked the Wikipedia page on "Exim", and it seems that this is for E-mail? I only use Web-based E-mail and never check E-mail in any "Outlook"-like application. Do I really need this to start? I can't seem to uninstall it, as it is used by `at` and `bsd-mailx`.

Debian 5.0.

Usually cron and some other tools will use a mailserver internally to deliver mail to eg root acct (accesible using mailx cmd at the cmd line) if it has a problem. See also integrity checkers like aide, tripwire.
Try logging in as root in an xterm and

mailx