Up until that time, Google Analytics displayed just "Facebook.com" and mobile "m.Facebook.com" as the referrers. You may have noticed the new referral sources as "L.Facebook.com" and "LM.Facebook.com" while perusing your Google Analytic reports.
There has been a lot of speculation online as to what the changes mean and what the data actually represents. But according to Facebook, they use a tool LinkShim that is behind the change.
Facebook directs all referrals through a LinkShim to protect clicking visitors that may access malicious sites by accident. When clicking on a link in Facebook, the tool checks the url against an updated list of malicious sites. If it detects one, Linkshim displays a 'warning' page designed to protect or warn people visiting the site. It is also used to protect any personal identifying information from third party sites.
What does this mean for Google Analytics? Since Linkshim provides a high level of security to users and with the new urls, more traffic that was originally from an unknown source now shows up as Facebook traffic and gives a better picture of referrals on platforms like Google Analytics. This upgrade was an improvement because the current Linkshim version use to register in Analytics without an accurate source attribution; you couldn't tell that visits were coming from Facebook, whereas now you can.
Your Google Analytics most likely now displays four different values for Facebook. These combinations of desktop/smartphone and Linkshim represent:
- facebook.com - desktop or tablet, link was not directed through Link Shim
- l.facebook.com - desktop or tablet, link was directed through Link Shim
- m.facebook.com - smartphone, link was not directed through Link Shim
- lm.facebook.com - smartphone, link was directed through Link Shim