I think I am 'Group 3'. My account is 4 1/2 years old and I was a 'read only' site visitor for a while before that.
So there were the people who got here first, then the people who discovered the site in 2008, which was a long time ago, and have fair claim to being 'group 2'.
So I think 'Group 3' is me. A defining characteristic of 'Group 3' is that goes back to pre-Snowden times, before the truth was known. Kids today must be 'Group 4'.
This reminds me of A Brief History of Who Ruined Burning Man:
https://journal.burningman.org/2016/10/philosophical-center/...