From the 1990s through the mid-2000s, it wasn't unusual to see a car whose bumper, or even entire back side, was encrusted with stickers of confrontational whining, smug slogans, adolescent humor ("Your mom's hot"), and/or a list of your favorite "edgy" bands. Cars with only a handful of stickers were more common still.
You don't see that anymore, and on the rare occasion that you do, it's clearly a fossil from that earlier era -- "Impeach Bush," "Fukengrüven," "COEXIST," "Mean People Suck," "Phish," etc. What happened?
Flashing to the world all of your annoying opinions and obsessions ("interests"), from behind a wall of anonymity, in a drive-by fashion, trying though often failing to smugly troll strangers -- sounds an awful lot like what the internet was made for. Or rather the web 2.0, when comments sections and social media were born. Only now the technology allowed you to annoy people all over the world -- get more bang for your broadcasting buck.
Although seemingly trivial, the case of bumper stickers illustrates an important point I keep making about technology and social life: technology doesn't make us use it any particular way, and a technology may only become widely adopted because users were already heading in a new social direction.
This is complementary to the standard view that technology colonizes our society, and we are unwillingly affected by it for better or worse. I don't deny that that happens, but it relies on the assumption that the users didn't really want it -- why not ask them first and see how enthusiastic they were to adopt it?
Thus, anonymous comments and social media did not tempt people into blabbing their confrontational, smug, gotcha! slogans to the rest of the world. That attitude and behavior was already highly visible back in the '90s, and even the 2000s -- right up until the web 2.0 opened its doors. Twitter did not set off the battle between SJWs and their counter-trolls; that existing culture war simply shifted arenas, from car bumpers to social media sites.
It also goes to show how little the difference between today and the '80s has to do with technological changes. People didn't have anonymous comments and Twitter back then, but they had bumper stickers and decals -- why didn't they plaster dozens of stickers on their bumper, using them for hostile crusading like they would come to do during the '90s? Quite simply because they didn't have that attitude.
The primary change between the get-along '80s and today is one of attitude, social stance, worldview, and so on, not technology. The '90s is the crucial decade to resolve the matter. Like the '80s, it lacked an internet with anonymous comments and social media sites. Unlike the '80s, people's attitudes had shifted toward cocooning and anxiety or hostility in social situations.
The social mood trumped technological constraints, with people of the '90s making do with bumper stickers for socially anxious confrontations: to wage SJW crusades (or to troll the SJWs in return), to blab their obsessions to the world, and to try out one-liners on an audience that can't respond by rejecting them.