ActivityPub spec bug: Relation between Actors and Users of servers is undefined

In short:
The #ActivityPub spec's problem is not in that simplistic phrase "users are
represented as actors here".
The problem is that there is NO technical description of the whole domain
model layer: relation between Actors (e.g. Person) and Users of servers.
Current version will be interpreted as having one-to-one relation between
the two *different* kinds of entities, and that *is* incorrect.

And I think that this gap will cause implementations, which will allow
neither having multiple User accounts for one Actor on different servers
nor (in particular) moving one Person's account between federation
instances without losing his/her identity, including historical data.

My view is that these features now become key features of a federated
social network, when people are searching for better places for their
social identities, when servers are being constantly created and shut
down...

A week ago I posted the bug report with concrete suggestions for a fix to
https://github.com/w3c/activitypub/issues/260

Let's fix the spec before its release, please!

-- 
Yuri Volkov, Business applications architect and developer.
Developer of AndStatus social networking client for Android.