For me, it was that the Internet never forgets and that you should never enter your real name. In my opinion, both of these rules are now completely ignored.
Every time someone does that it weirds me out because in the 90s telling (and asking) people those things would have been such a suspicious, sketchy move.
And now it’s come 180 in that some see it as a red flag if you don’t give up that information. I had someone on a different social media site accuse me of being a bot because I wouldn’t give up the specific town I’m from. I’ve seen it happen to others too. It is both fascinating and insane how viewpoints have changed regarding identifying yourself online.