To: Thomas Mercer-Hursh who wrote (32424 ) 9/27/2000 2:13:55 PM From: Don Mosher Read Replies (2) | Respond to of 54805 Hi Thom, I understand the ambiguity and the delight in playing with my language here. But, when I read what I wrote, the "physical" and the "virtual" were in separate sentences. Am I just confused? Or, are you just teasing?" I am sure there must be a more graceful way of expressing this distinction, but it escapes me? Dare I call it a senior moment? Is the distinction between "physical networks" and "virtual networks" important? Can social interaction be "virtual" or is "virtual" only applicable to a simulation of reality? Are we connected by a "physical link" when we talk on the phone or only in an intimate caress? Can someone clarify what I did not? I am sure that you are correct about the engineering meaning of "positive" and "negative" feedback. However, I do not believe that authors like Mauboussin or Shapiro and Varian are using the terms in this way. They have in mind a looser social science definition that is somewhat like the one I offered. Unfortunately, many authors are using the terms without any definitions, relying on context to help the reader to infer their intended meaning. So, I offered this definition, which is certainly open to improvement and revision. I did, however, like my distinction between feedback, increasing returns, and virtuous cycles since many authors simply interchange the first two and don't address the differences among them systematically. I would be happy to assign the term "Luddites" to the last 2.5% to adopt an innovation. I once had a Ph.D. student who would reward me for learning a little bit about computers or the Internet by saying, "Well, this means that you are not a complete Luddite." I like the idea of calling someone else that name for a change. Don