Snowden: Dropbox is hostile to privacy, unlike "Zero-Knowledge" SpiderOak
theguardian.com
theguardian.com
However, I think he has a point, here. SpiderOak's approach is much closer to the best one could do for privacy. Dropbox seriously prioritized ease of development and convenience over security. That may be the right commercial decision, but kind of sucks after Snowden.
The problem with SpiderOak is the UI/UX sucks, compared to Dropbox (which is stellar in that regard). This is a persistent problem with security tools. If I had $+inf, I'd donate design/UX/etc. time to various security tools -- that, plus code review and documentation, would be a lot more meaningful a contribution than just creating yet another PGP.js or whatever.
Anyway, it's too bad this post is getting censored (a story with less points and yet triple the age of this one was just on the frontpage). Oh well.
The problem with SpiderOak is that the client is closed-source, which makes all their claims nothing other than claims. You must trust them on this very "zero-knowledge" point. So, from a paranoid point of view, their security is no better than that of Dropbox (or GDrive or any similar contender)
If you really want something that has a sound design, that would be Tahoe-LAFS [0]. In my opinion the software is still too hard to install and configure for everyone, but it still is a very good solution.