A couple of major platforms like Facebook and Twitter, YouTube, have become in many places around the world a de facto public sphere. Especially in countries that have less than free Internet, less than free mass media. And these countries have transitioned from a very controlled public sphere to a commercially-run one like Facebook.
The Web We Lost
I can have my independent blog, but if it’s not being promoted through one of these networks, nobody sees it. If it’s not being injected in one of these streams in a format that’s consumable in one of these streams, that’s compatible with what they call native advertising, which is stream items that are ads, then it doesn’t get seen.