Which is why I'm here. (There, we finally get to the point.) Nope I haven't become an advertiser, as the above paragraph may have initially appeared to suggest.
If you sign up for an account via this link, I get some free space added to my own account. And yours.
I can vouch for this programme--I've been using it for my files ever since I stopped trusting thumbdrives.
(An important thing, which I took a while to discover: remember to check out the "Manage Sync Folders" area. That's where most of the programme's power can be found. I'm still exploring it.)