I divide all communication tools into 2 styles: synchronous and asynchronous. What is each? And what is each good for? Synchronous communication requires both (or all) parties to be present at the time of communication. This includes face-to-face discussions, phone calls, and instant messages (though not perfectly synchronous). Synchronous communication is best for situations when you need immediate feedback, understanding, acceptance, or acknowledgment from the other party. Typically, this is for urgent or important topics. Asynchronous communication does not require presence from each party at the same time. Examples here include voicemails, emails, newsletters, and mail. Asynchronous communication is best for two situations. First, it's good for one-way broadcast of information requiring little or no feedback. And second, it's good for non-urgent communication where follow-up does not need to be immediate. More about these communication styles next time...