Yummy FTP Watcher is a Mac-only app that monitors and synchronizes local and remote FTP/S, SFTP, and WebDAV/S servers. It can detect any changes made to the remote file system and automatically update the local copies to match. It also supports background transfers and can be set to sync at specific intervals. The app is designed to be lightweight, so it won't slow down your system. It also has a wealth of features like remote editing, automatic retry on connection loss, and more. With Yummy FTP Watcher, you can save time and keep your remote and local servers in sync.
Discontinued The program is no longer updated. The latest version, 1.7.2, released in May 2012, can still be downloaded from the official website.
GoodSync
Forklift
Syncany
WebDrive
Syncovery
FTPSync.pl
Flow
Discontinued "The Syncany core team is on hiatus for an indefinite period of time". See https://github.com/syncany/syncany