The filter-bubble is a term used for the way the content you consume online is used to tailor the content directed at you, especially by large entities like Google and Facebook and Amazon. It magnifies biases in feedback loops, creates sortitions of people online, and even leads to the point where two people can find completely conflicting things from the same search query, based on how the algorithm analyzes you.

The Filter Bubble by Eli Pariser is a very good read. It lays out many social dynamics of the Web today, including advertising and social media and third-party tracking.

honestly, I'm just tossing random algorithm marketing buzzwords around to make a point of how this is all techbro mumbo jumbo, but despite my dislike for the NYT, there's some interesting stuff about right wing radicalization in their rabbit hole podcast, you might want to check it out: https://www.nytimes.com/column/rabbit-hole