A community of practice used to mean a small group of specialists who engaged in face to face consideration of issues of mutual interest, resulting in innovative solutions to issues concerning their area of speciaisation.

Interaction between “connectors” with similar interests who inhabited other communities occurred in  a limited manner, often at gatherings such as industry conferences.

The application of the term now has been substantially widened by the use of social networking tools  in ways that are completely new, to the point where we now have communities of interest in areas that would never have supported a community of practice.

Sites like Flikr are a great example, ranging from broad communities of interest to very narrow communities of practice in highly specific techniques where the chance of a pre-net community of practice forming would have been virtually zero.