You will often have multiple ways to communicate a message to another person. Your choice of a communication channel should consider the amount of detail and context the message requires. The richness of a communication channel is determined, in part, by the ability to facilitate rapid, two$-$way feedback. This means that an instant message will be richer than a group meeting grad, because:

You can respond immediately to what the person is saying

You know that the person's message is intended directly for you

You are getting many types of information, not just one