I use any online service with the assumption that the things I put up there could likely become public, no longer anonymous, or what have you. I don't think this is overly paranoid, given how difficult computer security is.<p>To me; it would make sense if Dropbox stored everything encrypted (as in, encrypted pre-transfer), and you needed the private key to decrypt stuff, unless you specifically state that it is to be public. It just makes sense from a liability statement. That said, you can do this anyway as recomended in this article.
(<a href="http://lifehacker.com/5813873/how-to-add-a-second-layer-of-encryption-to-dropbox" rel="nofollow">http://lifehacker.com/5813873/how-to-add-a-second-layer-of-e...</a>)