Facebook will leave the office during the next few weeks, which means that user activity is now encrypted when it hits a Web server. This is mainly useful when you connect via a wireless network. HTTPS has become the default setting for Gmail users in the last year, and other Google properties, including security tool. Facebook warns that HTTPS will cause the page load a limp, and will cause page load to limp. In the future, this could become the policy of encrypting Google, which encrypts Google.
Source: https://thehackernews.com/2011/01/facebook-enhances-security-with-https.html