like qpopper in not allowing people with APOP activated to log in via normal
POP3.
Rather than `USER \fIuser\fR', `PASS \fIpassword\fR', inc sends `APOP \fIuser\fR
\fIdigest\fR', where digest is the MD5 hash of the unique string followed by a
`secret' shared by client and server, essentially equivalent to the user's
-password (though an APOP-enabled POP3 server can have separate APOP and plain
+password (though an APOP-enabled POP3 server could have separate APOP and plain
POP3 passwords for a single user). `\-noapop' disables APOP in cases where it'd
otherwise be used.