I think this is the most important part of the text: It was only when Jon teamed up with the technology writer Tobias Rose-Stockwell that we found what we beli

I think this is the most important part of the text: It was only when Jon teamed up with the technology writer Tobias Rose-Stockwell that we found what we believe is the thing that warped the fabric of social space-time. It was the introduction of the “like” button, by Facebook, in 2009, which Twitter promptly copied, combined with the introduction of the “retweet” button by Twitter that same year, which Facebook copied in 2011. Before 2009, social media feeds were almost entirely chronological—content was mostly personal (rather than political) and social media was not particularly polarizing. But once users had two super-fast ways to say what they liked, and could do so many times a minute, the social media companies had vastly more information on each user’s behavior, and they began to optimize people’s newsfeeds using algorithms that continuously improved the platform’s ability to engage users and keep them clicking.