During a number of conversations recently I realized something. This may be obvious to you, or you might find it mighty strange. But I can say with confidence that at this point in time, 2011, my communications hierarchy is this:
First place is clearly email. This is where everything happens, particularly for business.
Second place is Twitter. All the smaller coordination, as well as a large part of the input and inspiration, happens here. (In fact, a large part of organizing and advertising Cognitive Cities Conference was done through Twitter, too.)
Third place – and a distant third, too – is the phone. Cell phone, of course. Landline has become so ridiculously unimportant that between my company Third Wave, our office mates Yourneighbours/Gidsy and our resident freelancer Fabian we share one (!) landline phone – without ever running into a conflict there.
In between, but too hard to place in this hierarchy, are Skype and similar instant messengers as well as SMS and of course face-to-face conversations.
Even I myself was a bit surprised by how clearly the phone had been demoted like this, and how important and ubiquitous Twitter has become in my daily life. But there you go. Curious to hear about your experiences that way!