A store that asks for ID before letting someone buy a porn mag will have an employee check with their own eyes and then return the ID. By the time the person is out the door, any record of who they were is basically gone. The record is just in the fading short-term memory of the employee. If they turned right around that instant and went back into the building, they're basically as anonymous as they were the first time. If they interrogated everyone affiliated with the store, including the owner, nobody would know the home address of the person even though it was on the ID. The anonymity is even larger if you let a few days pass. Nobody will ever remember you for having bought that magazine or for having ever entered that store for that matter. They'll likely be different employees.

With online services, the identity would be tied to your account forever. A government would have the ability to review every passing comment you've made in your entire lifetime and know exactly who you are, who your family is, where you live, where you work, what your bank accounts are, etc.

Right, the practical privacy outcomes are dramatically different when the digital panopticon is up and running.

The expectation of privacy from random unaffiliated humans seeing me pass on the sidewalk is very different from being stalked by a drone swarm that follows me and whatever vehicle I'm in.

As others have pointed, this is unfortunately already true, due to big data and analytics companies hoovering up everything.

So again, what changes in any fundamental way?

This is a tech forum. There are already standards that can be used to verify age without requiring a lot of extra info. (Already used by drivers licenses at TSA checkpoints, those are all standards).

There are ways to solve this without essentially saying “there is no alternative so let’s give nefarious companies access to our kids brains all the time”

Just because it's bad, doesn't mean it's fine if it gets way worse. There's a difference between individual platforms potentially selling data with aggregators maybe finding ways to fallibly join them together, and the government mandating using a standardized identifier between all of them such that platforms can't even choose to be privacy-respecting.

You can use pseudonyms on practically all social media. That's under threat.

> There are ways to solve this without essentially saying “there is no alternative so let’s give nefarious companies access to our kids brains all the time”

It's ultimately the parents' responsibility, and the parents willingly gave their children access. It's very easy to setup parental controls. It's very easy to get your child a dumb phone. It's very easy to confiscate technology that their child isn't using responsibly. Adults should know that peer pressure isn't reason enough to give their children more freedoms than they're able to responsibly handle.

If people want to tackle this on a societal level, we should be looking into what's causing parents to be so lax in their parenting.