Amazon Advertising (formerly AMS or Amazon Marketing Services) is a service that works in a similar way to pay-per-click ads on Google.
Facebook pixel is an analytics tool that allows you to measure the effectiveness of your advertising.
Google Publisher Tag (GPT) is an ad tagging library for Google Ad Manager which is used to dynamically build ad requests.
Priority Hints exposes a mechanism for developers to signal a relative priority for browsers to consider when fetching resources.