To make the config changes take effect you need to send a SIGHUP signal to the proftpd process, whose id is in /var/run/proftpd.pid. Just type
kill -SIGHUP `cat /var/run/proftpd.pid`
whenever you make any config changes.
Just double-check that file proftpd.pid is in that directory; I don't know if it will necessarily be the same one on your system.
Yes, ftp users are just regular users.
[ March 03, 2004: Message edited by: flap ]