Hi!
We bought a Terastation NAS hoping to set up some sort of a "Selfhosted Dropbox alternative" which would allow each user it's own small, private space to backup their files automatically via a Desktop Client that would automatically sync.
I think OwnCloud (already suggested) would be a good way to handle this, though it could be done via any other way, like an ftp-based sync client like FTPBox, but if Terastation would automatically create each user folder, it would simplify administration a lot.
Thanks!