The Harvard law professor Jonathan Zittrain summarised the findings thus: “Overall, users notified of their friends’ voting were 0.39% more likely to vote than those in the control group, and any resulting decisions to cast a ballot also appeared to ripple to the behaviour of close Facebook friends, even if those people hadn’t received the original message. That small increase in turnout rates amounted to a lot of new votes. The researchers concluded that their Facebook graphic directly mobilised 60,000 voters, and, thanks to the ripple effect, ultimately caused an additional 340,000 votes to be cast that day. As they point out, [in 2000] George W Bush won Florida, and thus the presidency, by 537 votes – fewer than 0.01% of the votes cast in that state.”

via Could Facebook be a factor in the next election? | Technology | The Guardian.