Since the game shifts to the postgame lobby very quickly after it ends, people usually discuss the game they just played there for a bit. It’s a bit awkward, though, to go from using people’s in-game names to using their account names, since you have to constantly check the list of players to see who everyone was.
Since numbers are used for everything in-game, I suggest prepending player’s numbers from the games in front of their account name when they speak in the postgame lobby, eg:
“[1] Aquillion: Good game!”
That will make it easier to track discussions of the game without having to constantly cross-reference the list of users to remember who everyone was.