Facebook Experiments Had Few Limits"Thousands of Facebook Inc. users received an unsettling message two years ago: They were being locked out of the social network because Facebook believed they were robots or using fake names. To get back in, the users had to prove they were real. In fact, Facebook knew most of the users were legitimate. The message was a test designed to help improve Facebook's antifraud measures...'There's no review process, per se,' said Andrew Ledvina, a Facebook data scientist from February 2012 to July 2013. 'Anyone on that team could run a test," Mr. Ledvina said. "They're always trying to alter peoples' behavior.'...The recent ruckus is 'a glimpse into a wide-ranging practice,' said Kate Crawford, a visiting professor at the Massachusetts Institute of Technology's Center for Civic Media and a principal researcher at Microsoft Research. Companies 'really do see users as a willing experimental test bed' to be used at the companies' discretion."