The journal that has published the Facebook mood swings study regrets the way the study was conducted. Facebook issued a sorry statement for accessing the content of 700,000 people’s pages, but the company’s second-in-command said she has no regrets. It was concluded by the Proceedings of the National Academy of Sciences journal that the move to manipulate the content appearing on the Facebook pages of about 700,000 people without their prior consent may have violated some principles of academic research.