This is another productivity advice that I do not hear often. It is easy to apply and makes a difference for others as well. It is a “No-hello policy”, pretty well described here: No-hello Policy: How not be annoying.
The rule is simple - if we want to ask someone a question via chat, we should not say “hello” and wait for the “hello” response. Saying “hi”, “hello”, etc. is not a particularly bad thing, of course :). We should use that. It shall be immediately followed by the rest of the message, though. We do not want to distract someone only by the greeting and make the person waiting for the rest of our message. Or even worse - force him to respond with just a “hello”.
Still, lots of people do not know this rule. Therefore I strongly recommend waiting a while once we see a blinking message indicator to be sure that the full message is delivered. Even a better approach is to check chats and emails only periodically to increase our productivity, but this is a well-known tip.