I have unchecked the option ProFTPD virtual FTP in Features and Plugins but FTP is still working. How?

[Randomz]

It’s actually if you have available IP and want to have a separate IP for each domain to use FTP. Most (all?) people won’t use this.

See here.

how2 setup individual virtual ftp site per domain

Virtual FTP requires an IP per domain, and there is an option for it in the Create Domain form in the Enabled Features section (labeled "Setup IP-based virtual FTP?"). Anonymous access will probably require some tweaking to have it work the way you want. You’d probably want to use the group to allow users of the virtual server access to the outgoing directory.