Google is a US-based multinational corporation which controls a large part of the web. They control the majority of discovery through the Google Search and Google News products. They also control the overwhelming majority of revenue through their Google Adsense products.
Google's market control and power
Jason Kint, CEO of Digital Content Next, gave a really good summary of how much control Google has online in a hearing in the US Senate on June 16th, 2019.
Google Search is the worlds most popular search engine much thanks to it being the default search engine in both the Google Chrome web browser product and the Google Android operating system.
Google Android is the most popular operating system for mobile phones, tablets and smart televisions. It is based on a heavily modified Linux kernel. The kernel included in a typical Android mobile installation is heavily modified with proprietary code and drivers. The Linux kernel is free software, the Linux kernel found in most Android devices is not.
Google's Chrome web browser product is the most widely used web browser. Its mobile dominance is largely due to it being the default browser on the Android operating system.
Google AdSense is Google's advertisement network. It is the most dominant advertisement solution on the world wide web today. This is the Google product that generates the vast amount of Google's income.
YouTube is Google's video platform. It used to be for independent content creators. This changed around 2016. YouTube is currently more like a platform for large traditional news and media corporations.
Stadia is Google's gaming platform. Games are executed server-side and streamed to the end-users devices.