[mtgx]

They don't necessarily need to do that. What they could do however, is allow files to be encrypted locally before they are synced and uploaded to their servers. The vast majority of people would still not do it anyway, but those that care would.

I really like how Cryptomator works, and I think Dropbox could easily provide similar functionality, and perhaps in an even more user-friendly way, too, since they can just integrate it with their Dropbox app, rather than this functionality being in a whole separate application.

https://cryptomator.org

Dropbox is not an advertising company like Google. They still have some of the highest fees for cloud storage around. So why do they care about seeing what's in people's files? Why not allow people to encrypt the files locally before uploading them?

And lest we forget, in the PRISM slides, Dropbox was mentioned as "coming soon". So unless they want to admit they are already part of the PRISM program, then what better way to dispel those rumors (not made any better by getting Condoleezza Rice on their board) that they are cooperating with the NSA.

http://www.zdnet.com/article/fbi-nsa-said-to-be-secretly-min...

[flyt]

Take a look at nCrypted Cloud for an option: https://www.encryptedcloud.com/

Realistically, though, Dropbox can't offer many of the features that differentiate them in the marketplace (collaboration, previews, sharing, etc) if all of the files they store are opaque to them. Playing in the "generic blob storage" market alongside S3 is a losing game for pretty much everybody.

[incongruity]

AFAIK, right now, there's no convenient S3 desktop client that makes it trivial to automatically mirror and share folders, much less make client-side encryption of files trivial on top of all of the above. IMHO, that's a very viable niche... User experience matters – it's not solely about cost.

Also, about n-crypted cloud – last time I looked, the file size limit was 150 MB – that kills the utility for my team, but it's still a decent option from my experience...