I just saw this in a blog. I had never seen it before. Some probably have.
it's how to synchronize your "whatever" over many different platforms... seamlessly, sort of like how my Mac pushes info between computers and my phone. It's free for the first 2gb. There are pay plans for professionals.
Good for Mac, PC, Linux, etc...
I'm not related to the owners...just saw it, and thought it might be a neat thing especially if you are traveling, and need to get your photos somewhere all at once.