1) 'This is what makes most complaints in the facebook-makes-money-off-of-you vein a complete misunderstanding of technology. [...] For the purposes of advertis

1) 'This is what makes most complaints in the facebook-makes-money-off-of-you vein a complete misunderstanding of technology. [...] For the purposes of advertising, facebook does not need you to disclose relevant information to anyone but facebook.' You didn't understand cstross's sentence. He said that the social networks are motivating their users to disclose information [that is] relevant to advertisers; he didn't say that they are disclosing the information directly to advertisers. 2) Handwaving about applications and like buttons aside, it's pragmatically trivial through the facebook ecosystem to capture a great deal of data about individuals that they might not natively believe they are exposing. I know this because I personally do this (for benign reasons).