I see that RackShack is offering
APOP email protocol support
is that better or worse than having sendmail?
Bradley

APOP does not replace sendmail, the two deliver different functionality.

APOP is Authenticated POP - delivery of incoming mail received by the mail server to a mail user agent (email client that supports APOP - note, not all do).

sendmail on the other hand is a mail transfer agent, repsonsible for outgoing mail transfer.

well, MTA also is responsible for incoming e-mail as well:) It will deliver email to maildir or mbox format and pop3/imap will pick it up from there :) correct if I am wrong :D

Sometimes when answering a question its best to simplify... and given that the questioner was equating APOP with sendmail, simplication is the right approach, IMO!

An even simpler answer would be:

APOP is to POP as
Postfix is to sendmail