In my experience, the single biggest drawback to communicating online—whether it be email, tweets, instant messaging, or whatever—is the absence of tone.
Without voice inflection, body language, and other sensory clues, it is often difficult to accurate convey our original intent. It is equally difficult to fully receive a message in the way it was intended.
This is nothing new. We've all experienced these shortcomings, as well as the inevitable tidal wave of follow-ups and clarifications and, sometimes, apologies.
Allow me to share an excerpt from my youth which I am sure you are all familiar.
Irritated Parent: "Don't you use that tone with me young man."
Eye-rolling teenager (me): "What tone?!"
You know what I'm talking about, don't you. How we communicate can often be more important than what we actually say. It would serve all of us well to take a small step back and observe how we speak to others.
Are we loud or soft, biting or kind, quick-tempered or patient, brave or timid? The old saying goes that "how we do one thing is how we do everything." How we communicate just might be reflective of how we live our whole lives.
To your good fortune!