The most important platform to be closed off 2017-2019 was YouTube. Before 2017, YouTube was a very open platform, with easy monetization and almost no moderation of legal content. By the end of 2019, thoughtcrime (anything to the right of Ben Shapiro) was thoroughly purged.
In March 2017, several news organizations (The Times of London, the Guardian, WSJ) published coordinated articles about ads appearing next to "problematic" content on YouTube. This led to the British government summoning Google to explain and an advertiser boycott.
[as an aside, no one sane believes that an ad appearing next to a YouTube video implies the company behind that ad endorses or knows about the content of the video; this was 100% astroturf. No one knew or complained until the news articles hit]
Google then began restricting ads/monetization to large accounts that had been manually reviewed, and greatly expanded the scope of its hate speech policy (for instance, banning insults "associated with marginalization" - no points for guessing who defines that).
YouTube participated in the August 2018 deplatforming of Alex Jones (along with Apple, Facebook, Spotify, LinkedIn, Pinterest, Vimeo, and Twitter), permanently banning from the site. Jones' deplatforming was the start of a slippery slope.
YouTube expanded to more than 10,000 moderators in 2018. More than 90% of removed videos were seen by fewer than ten people.
In August 2018, YouTube also began banning state-sponsored content from Russia and Iran. This is less significant from a freedom-of-thought perspective, but I think sets a hard "no later than" date by which US intelligence agencies were getting involved.
In January 2019, Google began algorithmically suppressing "borderline content" meaning content that did not violate their guidelines but they judged could be harmful. Unlike bans, algorithmic suppression is silent and almost impossible to prove or fight.
By Dec 2018, Google was removing millions of videos per quarter, though mostly being spam or scams (which I think is justified, otherwise the site is unusable). But around 1% were for political reasons, and this number exploded in 2019 when moderation policy was changed.
Some of this zeal (more than 58M videos removed in Q3 2018) was to "demonstrate progress in suppressing problem content" to "government officials and interest groups [read: astroturfed NGOs]" who were (and are - see the UK's OSA) keen to control what is on YouTube.
In June 2019, YouTube demonetized and then banned Steven Crowder for calling a Vox journalist an "anchor baby" and a "lisping queer", which they acknowledged did not violate their policies [also note the Daily Beast calling insults "gay bashing," which they are not].
In Q2 2019, Google began "prohibiting videos alleging group superiority" [no prizes for guessing for which groups this was enforced] and as a consequence ramped up suspensions fivefold, banning more than 17,000 channels and deleting more than 100,00 videos and 500M comments.
Google eventually began banning "malicious insults based on protected attributes" [no points for guessing which attributes were protected or what counted as an insult] in December 2019.
In 2016, there was a thriving alt-center/"anti-woke"/anti-feminist ecosystem on YouTube, often connected to the New Atheists. By 2019, almost every major creator was banned, demonetized, or became leftist to survive, replaced by anarchist/Communist "Breadtube."
Since The Youth are illiterate troglodytes, video content served by algorithmic feed is their major source of information, and until TikTok (which has similar policies), YouTube was by far the largest source of this (by orders of magnitude).
As such, the purging of anti-woke/anti-feminists from YouTube killed any sort of semi-popular intellectual opposition to the Great Awokening under 30. The only site more emblematic of the annihilation of open internet discourse 2017-2019 might be Reddit.
In 2015, Twitter was "the free speech wing of the free speech party" according to CEO Jack Dorsey, even avoiding collaboration with the NSA (unlike Google, Facebook). By 2019 it was one of the most censored, monitored, and controlled social media networks in the world.
YouTube was the biggest and most monetizable platform, Reddit the most important discussion forum, Amazon needed for authors and websites, and Google Search the only way to surface niche info sources. Twitter mattered as the social network of the intelligentsia.
In 2015, Twitter under Twitter general counsel Vijaya Gadde began reinterpreting their existing rules much more broadly and banned hate speech, to "keep Twitter safe." Chuck Johnson was banned for tweeting that would "take out" (attack digitally, not murder) a BLM activist.
Alaric on 2010s feminism and sexual norms. He sees it as a concrete, sharp break in 2014 alien to anything that came before. which almost overnight made anti-male sentiment the most pervasive cultural force in the Western world.
2014 saw a huge top-down feminist media campaign both motivating and caused by government initiatives and international institutions. This was the true start of Woke as a feminist and internationalist movement, before it became more racialist and parochial.
2014 redefined consent and made rape and street harassment, low and falling for decades in the American mainstream, centerpieces of American social consciousness.
Another thread on the closure of the Internet. Amazon, like other major tech giants, had little content policy beyond "no illegal content, spam or scams/fraud" in 2015 and by 2020 had a well developed censorship infrastructure for both the web store and AWS.
Amazon is particularly important for two reasons: (1) AWS making it, like Google Search, a major Internet chokepoint and (2) 50% book and 80% e-book market share; Amazon banning a book is the closest a non-classified book can really come to being banned in the US.
The first cracks in Amazon's neutrality appeared in June 2015, when a media blitz and political pressure campaign (sparked by Dylan Roof) led to Amazon removing all Confederate flag (a completely normal American symbol) merchandise from the site.
WIRED: Silicon Valley gay networks are so influential because gays are "cross-generational" allowing settings where "established wealth meets emerging talent."
Gays run Silicon Valley, lesbians and fat people hardest hit.
There is a common Hollywood upwards mobility narrative for early 20th century European immigrants. It's not really true; for most origins earnings for both first and second generation were similar and were already above average in generation 1.
Relative rank order didn't change much either.
I know you might be wondering "why are Italians so high and Norwegians, Swedes, etc so low." Answer: farms.
More on the 2016-2019 closure of the Internet. In 2015, Reddit, like YouTube, had almost no content policy beyond banning illegal activity, doxxing, harassment, and involuntary or underage pornography. By 2020, Reddit had purged political dissent from the site.
Much of Reddit's shift was motivated by one thing: that r/The_Donald, the hub of internet Trump support, could consistently reach and dominate the front page. Reddit repeatedly changed their algorithm and policies specifically to suppress r/The_Donald before banning it.
The first major crack in Reddit's freedom of speech stance was in 2016, when the CEO of Reddit, Steve Huffman, was caught personally editing user's posts on r/The_Donald. He then changed Reddit's policy to exclude r/The_Donald from the r/popular Reddit homepage.