Paul Friedman, a 59-year-old dentist in New York City, says he's using Facebook less now than when he first signed on four years ago, but he's not sure if the site has "become less interesting or that I am just less interested in it, " he says.

NPR: As Facebook Matures, Is It Losing Its Edge?

Among young people who are interested in politics, Mr Crossley reports that they are likely to become less rather than more radical as they switch from sixth form to university.

BBC: Students ignore sex and politics

Fitzgerald is interested in what Sandberg calls the success and likeability problem: As women become more successful, they are less liked.

WSJ: The new book group? Women form 'Lean In' circles