Well, this was just scanning the public/ folders, the files in which are accessible to anyone that has (or, in this case, can guess) the link.<p>Now, if it's something you absolutely must keep private, you shouldn't even store it in the private parts of your dropbox folder, but for things where it's not a huge deal if it ends up public, Dropbox is reasonably safe assuming you're not stupid about it (strong password, etc).