There are plenty of blogs out there which have a myriad of uses for dropbox.
I have it installed on several machines including my phone, and my home server which is practically always on.
If you've not come across Dropbox before, you can find it at www.dropbox.com but if you follow my referral link ( http://db.tt/mEf8X4WA ) you will get an extra 250Mbs of storage space. (and so will I) ;-)
Here are a few uses I employ with dropbox. I may expand on this list at a latter date.
1). I have a directory called "Torrentfiles" which I use on my Andriod phone to download the torrent files for any large files I want to download.
I have my home server setup with Transmission (my favorite BitTorrent client) running and looking in the "Torrentfiles" directory for new torrent files.
When I place a file in there, it will automatically start seeding and downloading the file for me. (I've also got it set up to delete the torrent file when its finished).
2). I also use the public space provided by dropbox which I have used to host quick and dirty websites.
3). On a similiar theme I have been known to use the public space to distribute files between several Linux PC's on different networks using the "wget" command.
4). Storing photo's off my phone, so they are saved direct to my Dropbox directories. ;-)