idle technology thought:
The "@" symbol as used in email has a sort of poetry to it. It describes a person at a place. It symbolically embeds an understanding of the structure of the network.
Twitter's abuse of the @ symbol to address a *person* is the protocol design of a linguistic drift that results in semantic inversion, like the unfortunately popular "I could care less".
In a better world the fediverse would've retreated to custom-scheme URIs rather than double-@ addressing.