I have never heard of ETA meaning edit to add. I’m guessing FW means forward, I’m not sure if I’ve actually seen fwiw, and I think people just like IANAL because it has the word anal in it.
I agree with you on the til and eli5. I’ve seen these terms seeping out of Reddit as well.
One thing that made me honestly irrationally angry or somewhat disgusted is people saying happy cake day, and flopping their stupid emoji in there. My Reddit account was like 13 years old, and I never felt like I was missing anything there.
What appears to be the problem chap?