_fbp: Used by Facebook to deliver a series of advertisemen tproducts such as real time bidding from third party advertisers
_gcl_au: Used by Google AdSense for experimenting with advertisement efficiency across websites using their services.
ga-audiences: Used to detect whether the user intends to leave the page via cursor movements. This allows the website to trigger certain pop-ups to keep the user on the website or convert them tocustomer.