[captainmuon]

That's a good point! One favorite idea of mine is that you have a trusted identity provider, that knows you, and hands out pseudo-anonymous identities. E.g. Facebook vouches User123 is female, 20-25 years old, has been active for 2 years, and is likely not a spammer. This gives you disposable identities and the benefits of proven identity.

The problem with any kind of long-lived pseudonymous identity though is that it is really hard to do proper opsec and keep it distinct from your real identity, but I'm not sure there is a technological solution for that. I mean even your grammar can give you away (stylometry).