> The biggest problem with email addresses as 'permanent' identifiers is that people's email addresses change even within a single organization (for example, a

> The biggest problem with email addresses as 'permanent' identifiers is that people's email addresses change even within a single organization (for example, a university). They change for the same collection of reasons that people's commonly used names and logins change. True for some cases, surely, but I will be surprised if I don't go to the grave in ~40 years with my current gmail account still intact (assuming email is still a thing). I assume this is true for some appreciable fraction of email users, although I couldn't hazard a guess of what fraction.