“Unlike Google Display ads which target people based on cookies, Facebook lets you define and reach the exact target audience you want.”Pitch from the Facebook business page.
It is true. URL tags/Cookie-based tracking is old, inaccurate technology.
Why? Let’s say you saw an ad on Facebook. The link attached to the ad has URL params (i.e., “?country=US”). The params will be captured by the page you landed on. The site will drop a cookie on your computer (a text file) to identify you. Next time you visit the website, it will read the cookie file and know it is you.
That’s all it knows. For that matter, you are still a John Doe.
Identity-based tracking is a whole new game. When you create an account on Facebook, you are giving the company a lot of information about you (like your name, city, age., i.e. your identity.)
If you use Facebook on your desktop computer, mobile phone, tablet, you are telling the identity-based tracking system that is you.
Sites implementing the Facebook pixel can store your Facebook ID in the cookie files, and Facebook can track what you are doing across all the pages.
From an advertiser point of view, this is a very powerful tool. If you want to decrease the churn rate, you can create a custom audience on Facebook, targeting people who unsubscribed from your service and run ads to win them back.