The Fall of Data Haven Sealand
Fluffeh writes "Ars has a great article about the history of Sealand, a data haven — a place where you can host almost anything, as long as it follows the very bare laws of Sealand Government. Quoting: 'HavenCo's failure — and make no mistake about it, HavenCo did fail — shows how hard it is to get out from under government's thumb. HavenCo built it, but no one came. For a host of reasons, ranging from its physical vulnerability to the fact that The Man doesn't care where you store your data if he can get his hands on you, Sealand was never able to offer the kind of immunity from law that digital rebels sought. And, paradoxically, by seeking to avoid government, HavenCo made itself exquisitely vulnerable (PDF) to one government in particular: Sealand's.'"
Sealand has no practical sovereignty. The most they can say is that so far the UK hasn't chosen to take over, and they're not aware of any plans to do so. Nobody believes the UK couldn't take Sealand if they want to. Nobody believes that it would be a diplomatic problem for the UK in their relations with other countries if they did. So Sealand, at best, can operate only if the UK lets it. That's not sovereign in any meaningful sense. Even if you feel that it would be wrong for the UK to interfere, that's hardly something you're going to rely on to stop them doing so.