> For example, in the old days, the internet was scarce, so people had the sense that their online self and their real-life self were the same.

I’d argue the opposite. On the old internet we all used nicknames, and everyone knew not to share their personal info. These days nearly everyone posts stuff on social media using their real name and a photo of their face.

there use to be a saying "on the Internet, the men are men, the women are men, and the teen girls are FBI agents". It was very anonymous.

Reading your comment, I realize that the local context was something I had been missing, and your point makes a lot of sense. I think I should revise it like this

"The online self used to be an identity that was managed within small, persistent communities. Now, that self is easily discarded and reformed."

Thanks for the insight