I feel the same. I think the internet is so big everyone just lives in their own bubble.
Bubbles are usually created by biased phenomena that overindulgences on the rising stage of a hype cycle. The break out of interest groups or cliques or whatever on the internet is human behavior. Every country has different subcultures as well, so I wouldn't necessarily expect to fit into every group of a given country. The author is thinking of a bygone era when there was only a small subset of a given population on the internet, and they were all very similar people.