BitTorrent Sync is a new p2p tool which opens some fantastic possibilities. It may revolutionize the way you'll handle your private file sharing as it allows you to share & synchronize your files across multiple devices (PC, tablet, smartphone, ...) on the net in almost real time.
Some examples of the possibilities opened by BTSync are described in the article BTSync - How peer-to-peer may Simplify your Life.
As BTSync is a young project, you can get latest binary from the project site but you still don't get proper Ubuntu installation package handling BTSync daemon launched per user session. With this type of configuration, BTSync will be launched at login time with the current user's credentials.
This article explains how to install a BTSync daemon on a Ubuntu workstation with BTSync daemon being launched at session login using the user's credentials. It will allow your currently logged-in user to share files with a BTSync daemon running using current account. You'll get a synchronisation daemon equivalent to Dropbox.
It has been tested under Ubuntu 12.04 LTS 7 Amd64 but it should be applicable to any debian based distribution with little adaptation.