For a person with a multi-word name, you have to put quotation marks around their name to @ them. But only straight quotes will work, curly quotes don't. This results in failed mentions, especially on iOS, where quotes are made curly automatically.
For example:
@Fruit Fucker 2000 works. but
@“Fruit Fucker 2000” doesn't
(My last report for a while, I promise!)
Posts
It's much like an escape character in a programming or scripting language - in plenty of cases there are other grammatically identical characters, but functions aren't duplicated across them.