Yep, anon and semi-anon are certainly needed. My guess for a pseudonym mechanism would be borrowing someone else's ID as an umbrella. Going a bit abstract, that's what the Guardian is providing its staff, in that you just see "The Guardian", yet you will probably still be able to find favorite authors there even if they don't use their own special ID certificates.

I'm guessing this won't really (or doesn't _have to_) impede anonymity so much. Some kind soul will set up the "GeoCities / NeoCities of Online Identity" and from there it's just a question of whether you care how you are perceived while using that particular umbrella. Domain names would be the big losers.

But this is just my brand-new mental model for what's going on...