Recently we composed a lot of emails by hand. (We are also adopting this stupid way of saying that we really put in effort to write those emails.) These are the people who learned about the event concerning us second, right after those few we told in person. The third tier consisted of those who were only accessible on instant messaging systems. We chose to leave these for later because we couldn't afford the time to engage in instant conversations and what is worse is that most of the exchanges would be just formal words rather than well-thought advice. We actually did not want instant reply in this case.
In daily life, all those trivial instant exchanges keep happening, eating up huge trunks of time little by little, which could condense into a 5-minute phone call which is more heart-warming and effective. Instant-messaging has its niche, but it has become the dominant form.