Some interesting thoughts:<p>> First, it isn’t anonymous ...<p>I believe this is a miss understanding. We loose anonymity once someone is diagnosed, there is no way around that. But we should not skip on anonymity for everyone else. Else this whole project is doomed by the onset as we are simply building a massive 1984 style infrastructure.<p>> Second, contact tracers have access to all sorts of other data such as public transport ticketing and credit-card records ...<p>Which is debatable, but not a major problem as long as this is a largely manual ad-hoc process regulated by law and so expensive to execute that we only do it during emergency situations. It's totally different once we start building systems and processes around this to make it cheap and it ends as the new normal.<p>> Third, you can’t wait for diagnoses. ...<p>Surely a problem we need to improve upon. Likely a major logistics problem? Maybe something we should ask the military to take a look, after all logistics is something they might have an idea how to do right.<p>> Fourth, the public health authorities need geographical data for purposes other than contact tracing ...<p>Why would this need to be part of contract tracing? Currently this is done based on confirmed cases. Surely they are largely localized, especially since the stay-home orders.<p>> Fifth, although the cryptographers – and now Google and Apple – are discussing more anonymous variants of the Singapore app, that’s not the problem. ...<p>I agree, trolling, denial of service and school kids are going to be a problem. Could likely be solved by adding a formal gate for infected. Signing the test result with a public-private key scheme should do the trick to prevent any non-legitimate results being used to trigger events.<p>> Sixth, there’s the human aspect.<p>Interestingly I would have said this is the technology aspect. How many contacts will we miss because bluetooth low energy is not up to the job?<p>> Seventh, on the systems front, decentralised systems are all very nice in theory but are a complete pain in practice as they’re too hard to update. ... Relying on cryptography tends to make things even more complex, fragile and hard to change.<p>Seems solvable, considering we are talking about mobile apps, mostly always online, managed through central app stores and servers? Sounds doable.<p>> But the real killer is likely to be the interaction between privacy and economics. If the app’s voluntary, nobody has an incentive to use it, except tinkerers and people who religiously comply with whatever the government asks.<p>Tend to agree, although we have seen quite some adherence to sensible rules the last couple of weeks. Maybe we will be surprised by our fellow humans, maybe not.