Did YouTube invent using an @ symbol to indicate talking to a specific person?

[Viscera]

Now I see people using that everywhere, including YA.
I wonder which staff member specifically can be credited and what they think of this interesting internet linguistic phenomenon.

[Rejay]

more $$$

[Frizzy Head]

No, actually, Twitter started it. Everyone is using it now just cos it's simpler.

[RXTicTac]

Actually Youtube didn't start it.
Not even twitter started it.
I'm not sure where it started but it just makes sense that you write @in front of it so they see it in their inbox etc.