A friend asked recently about Twitter, which is not the easiest thing to explain. As I thought about this, it struck me as pushing out the end of what is a spectrum of communication media. In modern times the ability for an individual to communicate, across great distances, and with ever increasing speed, has allowed for a number of new forms of communication to emerge. Consider the following diagram (click to enlarge), which shows the evolution of one-to-one communication methods (from snail mail to email and text messaging) as well as one-to-many methods (journals to blogs and now to twitter). As the speed of communication changed, the formality has almost universally decreased. But one interesting feature is that the potential audience has changed. Blogs, for example, are often read by a small number of friends and family members, yet they are open to the public, and can be found by people you never would expect to find them. Overall, this has led to an increase in transparency, a personality aspect that has become quite highly valued. What's the point? Twitter is yet one more extension of the ability to communicate with others, no less valid than a research journal. It's another tool in our communication toolbox, and one whose value lies more with the desires of potential readers than with the content of the message itself.