FTPbox - FTPbox is an open-source application that allows you to synchronize your files to your own host...
Link Shell Extension - Link Shell Extension (LSE) provides for the creation of Hardlinks , Junctions , Volume Mountpoints...
Dropbox - Online Sync and File Sharing
Symlinker - Symbolic Link Creator. GUI for mklink, Microsoft Windows symlink utility
Syncany - Syncany is an open-source cloud storage and filesharing application.
FileMenu Tools - FileMenu Tools lets you customize the context (right-click) menu of Windows Explorer.