clevercactus share is a private and secure environment to share files with people you know. It is simple and easy to use, it is free for individual users, educational institutions, and non-profit corporations, and it runs on Windows, Mac OS X, and Linux.
Groove is the business alternative to this.
You can also try this DIY method with your ISP's FTP account, or a 3rd-party account using FTPSync.
Here is an awesome idea for an all-encompassing file synchronization tool. All applications should share your preferences on the internet, so that when you login to your PC, your mobile, or your laptop, or a friend's PC, it instantly recognizes who you are and sets up your desktop the way you like.
The tool should synchronize your mail, bookmarks, contacts, links, music playlists, start menu, buddy lists, ftp, saved games, etc. etc.
It should allow you to right-click on an application in the start menu and select Synch Preferences, or right click on the start menu and select Synchronize All Applications.
You should have a management tool to synchronize all preferences and setup locations for files and preferences to be synchronized.
There should be an autodiscovery of common preference locations and updates via a web service, to make it easier for the non-tech person to figure out how to do this.
Maybe I should start this project up on sourceforge.net
I still want to get my Sync Up Your Car idea going. Having my stereo stolen every few months is a bit frustrating, and it would help if the only thing in there was a removable face with a USB connector. You can't steal something that's not there.
A good idea would be to embed the technology into the dashboard. I would buy something with Digital Rights Management just so I could find out when it was plugged into somebody else's car. Then I would sic my dog on them.
What could you do if you had a USB connector in your car? How about dial-up or wireless internet? Maybe Bluetooth-enabled cars?
