In the absence of an authority in this field, Privacyscore is a private initiative that offers a rating from 0 to 100 to websites, based on the way they use or transmit user information.
WikiPedia is one of the few websites that managed to get a score of 100, while any website with a score under 50 becomes dangerous for your private information.
PrivacyScore, available also as a Firefox extension and Chrome, gave scores to more than 1,500 websites so far. The website offers other tops too, tops showing you the most secure or insecure websites.