To be fair, when I was a teenager 20 years ago in the 2000's chatting on AIM or MSN Messenger:

- Most people didn't capitalize

- People used a blend of text and regular emojis

- Acronyms were rampant... "sup", "nm", "wbu", "wyd", "brb", etc...

- Many of the same rules applied re: use of periods, having different meanings for "okay" vs. "kk" vs. "ok"

These rules started to form 20 years ago. Not new to this generation.