Facebook offers a new service. You can now use Facebook to anonymously log in to a third party website. That is incredibly convenient, and great news for online privacy. Or is it? Facebook still knows exactly what you're up to. The sites in question might only get the confirmation that you exist on Facebook, but you hand over the keys of your online existence to a company that has showed time and time again it cannot be trusted to abuse it. So if you see a button 'log in to Facebook', what do you do? Do you choose to use the convenient route? Or do you look for that hidden option to log in without Facebook?