Privacy advocates may still envision a world where most people keep their personal servers in data centers as a sort of snooper's Disneyland, because a global a

Privacy advocates may still envision a world where most people keep their personal servers in data centers as a sort of snooper's Disneyland, because a global adversary could just trawl the whole machine room and get everyone's data. Physically, this is true. But politically, a well-designed personal server ecosystem is more robust than it looks against this attack. The key is, as Kenton points out, server mobility. The server that's your whole network identity has to be able to migrate easily, even automatically, between hosts public and private. One way to think about how mobility makes a personal server more private -- even against a global adversary -- is the epidemiological concept of "herd immunity." For any global network, the percentage of users who demand absolute privacy is small. It works better to host your machine in the cloud. But the costs and pain points of closet hosting are acceptable for this specialty market. What's not acceptable is a situation in which the pro-privacy users form a small isolated network which can only talk to itself, losing on Metcalfe's law. Instead they need to be externally indistinguishable from normal users. Moreover, they need to be able to switch back and forth from absolute to relative privacy -- cloaking and uncloaking, as it were. Normal users care only about relative privacy, ie, security against all non-sovereign adversaries. Excellent relative privacy is available from an ordinary data center. "Linode hacks" happen, but less and less often. But actually, just as the privacy-conscious users can blend into the herd of normal users, the normal users benefit from the small minority of privacy-conscious users. Any global adversary has to assume that anyone with something to hide has probably hid it already. So cost-effectiveness concerns decrease the adversary's motivation to search in data centers. Why would anyone with anything to hide, not hide it at home? Home searches are much more difficult. Moreover, most people computing at home probably have nothing at all to hide -- they are just normal people who care about privacy. So as long as they stick up for their digital rights, the global adversary remains politically quite weak.