I'm finding this discussion of counterfactual history fascinating, but I am more intrigued by the discussion of what, exactly, constitutes a "failure" (apologies to Bob Dylan). That topic arose in a recent paper I gave about a failed information retrieval system developed by Calvin Mooers, in which I argued that although he failed commercially, he nevertheless made significant advances in computer science, upon which a lot of modern computing depends. One member of the audience remarked that my discussion of failure/success may not have much explanatory value for historians (I can give more details off-line). More relevant to this discussion is a recent exchange on Quora over the failure of the IBM operating system OS/2 as it went up against Microsoft Windows. The discussion goes well beyond the journalists who wrote about it a decade ago. Here is the link: https://www.quora.com/Why-did-IBMs-OS-2-project-lose-to-Microsoft-given-that.... Best, Paul Ceruzzi ceruzzip@si.edu<mailto:ceruzzip@si.edu> 202-633-2414