For those of us who work on different computers in different locations, this is a great solution. I install it on all my PCs (it also works on Macs) and simply drop any files or folders I want available elsewhere into the Dropbox  folder on my desktop. Dropbox synchronizes the files to Dropbox’s central storage in the cloud, and down to all my computers while they’re on.
There’s also a web interface where I can see my stream of upload/download/delete activities and undelete what I’ve accidentally deleted. And I can create public URLs for files I want to share with others.
2GB of storage are included in the free version, and you can pay $9.95 per month for 50GB of disk space if you need it.
Brilliant, simple, effective – it’s what SkyDrive and Groove should be. Suggestion to Microsoft: buy these guys & bake it into Office or Windows. It’s really great.