I was not going for exact years but some semblance of "around then" which conveniently rounded up to the nearest decade. The Apple II was 1978 and the PC was 1981. I agree that the GUI should be listed as 1984 in some official capacity (or is it 1978 with PARC?), but most of the world and I were using text mode by default in the 80s; it wasn't until Windows 3.1 (1990) that the GUI became the default. Similarly the internet was around before 2000 but became The Thing with the dotcom bubble (maybe this one should be called Google instead of Internet since I already put DARPA at 1970. Maybe 1970 should be UNIX instead?). Anyway I don't think this detracts from the larger point, which was that these huge shifts do seem to come along about once a decade in the computing sphere. Oh and we forgot to mention virtualization/cloud, is that more or less of a paradigm shift than Google and the smartphone?