TechCrunch has discovered a major security flaw on Facebook that allows users to view the private chats of others, as well as their pending friend requests. When users go to their privacy settings, the "Preview My Profile" feature makes the chats visible. Facebook Chat was down Wednesday afternoon as the company tried to fix the glitch. The social networking site came under fire for its privacy settings with the announcement last month of its "Connections" feature. Civil liberties groups criticized users' inability to easily opt-out of new features.