Facebook Update Alert! 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.
You go shopping on a website, browse through some products, but decide you’re not ready to buy. You leave the site and go to Facebook and the first thing you see is an ad for the store or products you were just shopping. Those ads are possible because that store’s website has a Facebook Pixel.