... the campaign literally knew every single wavering voter in the country that it needed to persuade to vote for Obama, by name, address, race, sex and income.
...the digital-analytics team, led by Rayid Ghani, a 35-year-old research scientist from Accenture Labs, developed an idea: Why not try sifting through self-described supporters’ Facebook pages in search of friends who might be on the campaign’s list of the most persuadable voters? Then the campaign could ask the self-identified supporters to bring their undecided friends along.
...They started with a list that grew to a million people who had signed into the campaign Web site through Facebook. When people opted to do so, they were met with a prompt asking to grant the campaign permission to scan their Facebook friends lists, their photos and other personal information.
So, they used Facebook data, including "Friends" lists and personal information that those "Friends" had never directly consented to providing to the campaign.
 How did Facebook react to the much larger data harvesting of the Obama campaign? The New York Times reported it out, in a feature hailing Obama’s digital masterminds:
The campaign’s exhaustive use of Facebook triggered the site’s internal safeguards. “It was more like we blew through an alarm that their engineers hadn’t planned for or knew about,” said [Will] St. Clair, who had been working at a small firm in Chicago and joined the campaign at the suggestion of a friend. “They’d sigh and say, ‘You can do this as long as you stop doing it on Nov. 7.’ "
In other words, Silicon Valley is just making up the rules as they go along. Some large-scale data harvesting and social manipulation is okay until the election. Some of it becomes not okay in retrospect. They sigh and say okay so long as Obama wins. When Clinton loses, they effectively call a code red.