"These rules that we think of as privacy rules are not only for the sake of the individual, " Ms. Nissenbaum argues.

WSJ: Selling You on Facebook

Ms. Nissenbaum, author of the book "Privacy in Context, " has called for the development of what she calls digital "fences" around data usage.

WSJ: Selling You on Facebook

Helen Nissenbaum, a New York University professor who studies privacy, said that "Girls Around Me" generated outrage because it violated social norms against stalking women.

WSJ: Selling You on Facebook

Even so, many people who consent to sharing data online don't realize the additional intimate details that researchers can glean from it, said Helen Nissenbaum, director of the Information Law Institute at New York University, who wasn't involved in the study.

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