Spying on connected users. See all their commands issued, their current dir, the permissions for that dir, bytes sent, bytes received, speeds on current transfers, login time, login IP, etc. Both can be temporary per session login or permanent. Invisible mode allows the server to run without any windows. SITE commands for remote administering from an FTP client.
Custom responses for a lot of server responses.
You can edit them to fit your style. New features are constantly being added. Sign on a guest with a password of tfsysop if requested.