> The whole point of being open sourced is that you can compile them yourselves after your verification and use the product of your own compilation with the server-side of spideroak.

So this is a good point, however:

> More realistically, your distribution maintainers will verify and compile the package, and you trust your distribution maintainers more than spideroak so you delegate source verification to them.

This is actually pretty compelling, but ignores Windows and OSX devices, which not only are the vast majority of all users, but also the least likely to compile their own. They will trust the provided binaries instead.

This is one of those "Why Johnny Can't Encrypt" (http://www.gaudior.net/alma/johnny.pdf) situations. I'm not solely criticizing spideroak here, I think this is a more general open problem with any 3rd party service that's meant to be trusted. It's an oxymoron that's been only somewhat breached because of public key cryptography.

Windows and OSX devices are already trusting a huge lot of binaries compiled by companies that we already know that have been compromissed.

Or, in other words, nobody that cares about privacy are using those anyway (at least while they care about privacy), by definition.