Why thinking about this? Thing is that work tends to be more and more distributed and the temptation to use the modern communication methods like email (in one form or another) and instant messaging is bigger than ever.
Before going any deeper into this, let me first admit that I do not have an scientific data/evidence or other sound foundations for my theories. All of this comes from my own observations and the writings of others (namely Alistair Cockburn).
So, what is the most effective way to communicate? IMHO the best way to communicate (two persons up to small teams (about seven people)) is a vis a vis scenario with flip chart or white board. This way you can talk, listen, sketch, see, feel, smell. You see the reactions (say emotions) of people, you can even stop in the middle of a sentence if people do not react as expected.
The more I do in terms of (project) management the more I value this form of communication. My feeling is that the effectiveness (and risk) of communication is dropping quite significantly if you go from live to video conference to telephone conference to instant messaging to email.
Why is this? In the end of the day, communication is the interaction between human beings. We have a long history of implicit knowledge in communicating to each other vis a vis. This is what we are conditioned to since a couple of 1000 years…. We use a lot of our senses.
With video conferencing you loose smell (let alone that most people are feeling uncomfortable in front of a camera and “act” unnaturally).
With telephone you loose seeing emotions and reactions.
With instant messaging you loose hearing emotions.
With email you loose interactivity.
So, what’s left? A lot of room for misunderstandings?!
Please do not get me wrong here. I do like the modern means of communication. Sometimes it is so much easier to write something in a brief email instead of having to talk to someone extensively, it is even very essential if you want to document things. But I do think that you should choose the best possible (say effective) way of communication if the topic at hand really matters to you.