No I think it's the opposite, or at least, every situation is different. Consider a one-on-one chat (either over an instant messenger, or face to face in person

No I think it's the opposite, or at least, every situation is different. Consider a one-on-one chat (either over an instant messenger, or face to face in person). The period of time after which it becomes an "awkward silence" is much shorter in person. If I ask somebody a question in person and they take 5 mins to respond then that's a pretty ling awkward silence. If I message somebody on Slack and they take 5 mins to respond then that's not unreasonable. You could argue that the "Seen" feature of chat is meant to lower the acceptable wait time online, and indeed it does, but still not by as much. If somebody has "Seen" my message but doesn't reply after a couple mins, I'll start to wonder why, but usually my reasonableness kicks in and I think maybe they just are busy or didn't mean to click the notification or something. I'd still wait far longer for somebody to respond to a "seen" message than I would for somebody to respond to a "heard" question I asked them in person.