I'm using Sync for several things, but there's one small, simple, fantastically convenient use that I'd like to share with the community. I use a password manager (Password Safe, but this concept would work with any of them) to store all my myriad passwords. I use BTSync to replicate the database on my home desktop, my laptop, my Android phone, my partner's phone, and my work desktop. Not only are all our passwords securely available on all those devices now, but if one of us updates a password or creates a new login to some new online service, it's instantly available to us both wherever we are. For example, I created a new login at me health insurance company's website today. That's something that we both need to be able to access any time. Highly recommended.