I have a long time suspicion that browser leaks IP even if behind a proxy or a vpn. This article kind of proves it. https://www.tunnelbear.com/privacy/webrtc/ Reason being, sometimes you know you've never done shit and are very careful to secure your accounts, but shit still happens. Nowadays anything is possible. And this is just a +1 amount thousands of methods for social sites to bust your ass. Add: Just visit https://diafygi.github.io/webrtc-ips/ from chrome/firefox on windows and try it with a vpn like anchorfree, and you will see your IP is leaking. Now test this on IE, and it shows nothing.