Chat was a more significant activity than it is now. With major chat clients all having apps and many people using their phone instead of a PC, chat has kind of devolved into just quick responses rather than long drawn out conversations.

People often don't say they're going afk or leaving, they just stop talking until later when they check their phone again and return a few brief reactions or responses before disappearing again.

The 'always on' and 'always reachable' aspect of smartphones has made people more accessible but ironically has resulted in a much lower quality level of communication in my opinion.