Half the price of dropbox, this is just begging for a kick ass desktop/mobile app.
And I want a pony.
No client sync software, no sharing. I think the Dropbox folks will sleep well at night.
Smooth client software is half the value of paying for Dropbox and I don't see an Amazon side project challenging Dropbox in client usability anytime soon.
This looks more like a middle finger to any eventual iTunes cloud strategy.
In the coming weeks/months, expect to see rapid iterations...i.e. I wouldn't be surprised if they announce a desktop-side client in relatively short order.
How on earth does a large company like Amazon manage to keep pushing out so many innovative products so frequently.
Right now, this is not super useful - those of us who always early-adopt stuff like this probably already have Zumodrive and Dropbox accounts, as well as our own S3 accounts. In it's current form, this is not quite as useful as Zumodrive, which I've stopped using because Dropbox works so much more nicely.
If I were the Dropbox people, I'd be busy keeping the development moving forward to make it even easier for non technical people to understand what they are and use it, to ensure Amazon are still behind when they finally catch up.
(I'd also consider seeing whether I could match Amazons "mp3's purchased thru Amazon are stored free" offer - I'll bet Amazon are doing that with some smart de-duping filesystem magic which means they only have to store one copy of the mp3 file. I wonder if Dropbox are big enough to be able to gain major wins from that too...)