<p><pre><code> SpiderOak is a "zero knowledge" backup provider.
This means that we do not know anything about the data
that you store on SpiderOak -- not even your folder or
filenames. On the server we only see sequentially
numbered containers of encrypted data.
</code></pre>
This is really cool, and is a reason I don't use my dropbox for as much stuff as I would like to use it for. SpiderOak looks like something I would use for all my data, for this reason alone.