Many years ago, someone told me a little heuristic to determine if any new technology is likely to be successful. It doesn't always pick winners, but it rarely

Many years ago, someone told me a little heuristic to determine if any new technology is likely to be successful. It doesn't always pick winners, but it rarely picks losers: [_] Can this be used for porn? I think we have a winner here. (Other examples: 8mm film, VHS, the Internet, newsgroups, JPEG, streaming video, etc.)