Last week, I noticed that Facebook had started to attach a query parameter called “fbclid” to outbound links. I only noticed this because referral traffic from Facebook started appearing with the “fbclid” parameter in my Google Analytics dashboard.

What does it do?

This is some sort of new tracking mechanism that Facebook has implemented. It looks as though Facebook is rolling out a first party pixel implementation. This is probably in response to recent news that browsers such as Safari will be blocking 3rd party tracking cookies.

The term “fbclid” probably means “Facebook Click Identifier”. Google has a similar parameter called GCLID, which stands for “Google Click Identifier”. The Google GCLID parameter is used to transfer info between Google Analytics and Google Adsense.

What I did notice is this:

When I visited the BBC Facebook page in incognito mode on my desktop PC, the parameter was not attached to any of their outbound links.

When I logged into Facebook on my desktop and checked the BBC Facebook page again, I could see that all outbound links had the fbclid parameter attached.

I visited an outbound link using the browser that is built into the Facebook app on Android and the parameter did NOT appear.

appear. When I used the mobile version of the Facebook website on Chrome on Android, the parameter did appear.

After doing a quick search on Google, I have noticed that a few websites have already had their pages indexed with this new “fbclid” parameter attached. Another good reason why you should always explicitly set the canonical URL for each page: