"You're out joking around with friends and all of a sudden you're being used to advertise something that had nothing to do with what you were joking about with your friends," Boyd said. People don't hold conversations on Facebook for marketing purposes, she said, so it would be incorrect for marketing efforts to capitalize on these conversations.
In the article, this concept was described as "relatively new." I'm not sure that that's correct. After all article 6 of the EU Data Privacy Directive provides that
1. Member States shall provide that personal data must be:
(a) processed fairly and lawfully;
(b) collected for specified, explicit and legitimate purposes and not further processed in a way incompatible with those purposes. Further processing of data for historical, statistical or scientific purposes shall not be considered as incompatible provided that Member States provide appropriate safeguards;
(c) adequate, relevant and not excessive in relation to the purposes for which they are collected and/or further processed;
(d) accurate and, where necessary, kept up to date; every reasonable step must be taken to ensure that data which are inaccurate or incomplete, having regard to the purposes for which they were collected or for which they are further processed, are erased or rectified;
(e) kept in a form which permits identification of data subjects for no longer than is necessary for the purposes for which the data were collected or for which they are further processed. Member States shall lay down appropriate safeguards for personal data stored for longer periods for historical, statistical or scientific use.
which appears to be analogous to the concept of recognizing the context in which data is provided when deciding how that data should be used.
Of course, the question of whether an idea is a new one is entirely different from the question of whether the idea is a good one. However, recognizing the similarity between the proposed context limitations on social networks and the EU's data privacy directive can certainly be beneficial in evaluating the merits of the new idea. Specifically, the criticisms of the EU directive (e.g., here) can be examined to see if they also apply to the specific context based limitations, and if context based limitations can somehow be implemented in a way that addresses those criticisms.