I'm old enough to remember when it was celebrated that 'big data' was being used to rally voters.

https://www.technologyreview.com/2012/12/19/114510/how-obama...

This was in 2012.

These tools were used around the place. They have an influence. They don't decide who wins and what big issues are.

I'd date it to around then, too, but for a different reason. Whether you think it was a good or bad thing, I don't think it's incorrect to characterize the pre-2010s web as "socially progressive libertarian". 2013 was the first time I (we?) saw unabashedly extremist right-wing sentiments break Stormfront/4chan containment (and as a deathly serious matter, rather than the ambiguously sardonic nature of the latter's meme-ing). Specifically, with the Trayvon Martin/George Zimmerman murder trial, and the way that that incident picked up a thread of America's deepest divide and dragged it into cyberspace. I had never heard people saying the things they were saying around that topic, things that would make an Xbox Live edgelord go, "Bro, dial it back," and certainly never from the people who were saying them. My parents never saw the need to give me "the talk", and that was my introduction to the fact that America was very much not "post-racial", in a real way, and often proudly so.

At the point, everything was on the table, and everyone was "welcome" into the everlasting flame war.

> I would date this beginning to 2013. That's around when Facebook feed ceased to be chronological. That's when everyone became rabid.

I'm not sure how old you are, but I remember things being pretty rabid in the 1980s.