Facebook's still trying to brush off that whole psychological study with unaware users thing, but according to a former team member and outside researchers, the social network's data science department
has had (changes have been promised) surprisingly free rein over how it polled and tweaked the site. Andrew Ledvina, who worked as a Facebook data scientist from February 2012 to July 2013, told the WSJ: "Anyone on that team could run a test."
In 2010, the research team gauged how "political mobilization messages" delivered to 61 million users affected voting in the US congressional elections that year, while in 2012, thousands of users received a warning that they were being locked out of Facebook. While the reason given was that it believed they were bots or using a fake name, the network already knew that the majority were real users -- it was apparently all in aid of improving Facebook's anti-fraud system.