The betamax vs. VHS example is excellent as it was not at all about advertising but about content. Beta failed because Sony refused to permit porn to be distributed, thus preventing people from buying what they really wanted on their video recorders. Similarly, all these new computing devices will succeed or fail on content. To date, Apple has been a master of this. For the eDGe to succeed in the student market, student content will have to be plentiful. I surely hope that the etextbook "tab" is soon populated with textbooks.