Think twice before posting anyone\u2019s photo on Facebook, WhatsApp or Instagram, says free software guru Richard Stallman. As a few among the strongest centralised surveillance mechanisms in the world, even with a picture of the back of head, they would be able to track where you go and what you do, he added. The software guru\u2019s lecture titled Education Freedom Day lecture, organised by International Centre for Free and Open Source Software and Society for Promotion of Alternate Computing and Employment (SPACE) in Thiruvananthapuram, had first bewildered information technology professionals and academicians when he asked them to \u201cswitch-off the geo-location feature of your smartphone, if you are taking my photos\u201d. He said that 90% of the 1,000 free applications in Google Play stores can spy, according to the latest studies and asked why should the fleshlight application be linked to the server. Even the data on the sex toy go to the server, with its thermometer readings sharing the time of contact. He argued that owners of the firms who spy on a user\u2019s personal data should be jailed. Richard Matthew Stallman, according to Wikipedia, \u201cis an Amercian freedom activist and a computer programmer. He campaigns for software to be distributed in such a manner that a user receiving it, likewise receives with it the freedom to use, study, distribute and modify that software\u201d. Stallman swears he hasn\u2019t ever dialled for Uber services. He also stays clear of Netflix. Even if you read an e-book bought from elsewhere on Amazon\u2019s Kindle and the title of the page you read, the highlights you made and the page numbers would promptly reach the Amazon server, he said. SPACE, which invited the founder of free software movement for the lecture, is a Kerala government IT department-supported registered society, with members from IT industry, academia, professional societies like Institution of Electrical Engineers and the Computer Society of India.