Facebook Messed with Voter Turnout in 2012

On election day you may see posts on Facebook from your friends saying they voted. Turns out you're part of a big experiment by the social media site.

Facebook researchers have been looking at how sharing information about voting socially can impact turnout. In 2010, they put different versions of the "I voted" message on the pages of about 60 million Americans. They found about 20% of users who saw that their friends had voted also clicked on the "I voted" message. They estimate Facebook helped boost voter turnout by about 340,000.

Mother Jones says they tried a similar experiment in 2012, but this time it was a little more insidious.

Most but not all adult Facebook users in the United States had some version of the voter megaphone placed on their pages. But for some, this button appeared only late in the afternoon. Some users reported clicking on the button but never saw anything about their friends voting in their own feed. Facebook says more than 9 million people clicked on the button on Election Day 2012. 

Facebook's experiments in 2012 likely pushed more Obama voters to the polls than Romney supporters. How much they boosted turnout for the Democrats remains to be seen.

Facebook is again deploying its voter tool for the 2014 election, but they say they will not be experimenting on users this time around.