Pixels are common across most advertising platforms. They are used to drop a cookie that will track visitors on your website so you can advertise to them later. This is called retargeting. Once you advertise to past website visitors, pixels can also be used to track their behavior when they’re back on your website. This helps you measure the effectiveness of your ads.
To improve your ads delivery, how Facebook measures the results of your ads, and in an effort to enhance the relevancy and usefulness of ads, we’re enhancing the Facebook pixel. The Facebook pixel will start sending more contextual information from your website to better understand and categorize the actions that people take on your site to optimize for ads delivery.
The additional information sent through pixel will include actions on your page, like “add to cart” or “purchase” clicks, and will also include information from your page’s structure to better understand context associated with these actions.
If you created your Facebook pixel before April 20, 2017, this new functionality will go into effect on May 20, 2017. For Facebook pixels created on April 20, 2017 or later, this change will take effect immediately.