Non-ActivityPub actors

[ghost]

It appears that all actors must be resolvable ActivityPub members with ActivityPub actor URIs and inboxes and outboxes. We had this same problem with Diaspora. By forcing everybody in the network to be a network member, you can't federate with anybody outside the network - by design and mandate.

We solved it in the Diaspora case by turning activities by external federated actors into 'reshares' provided by somebody with a federated account (such as the conversation owner). It's a butt-ugly solution but it works and allowed us to federate GNU-Social comments into Hubzilla conversations that were viewed on Diaspora.

The same solution could work here, but it would be much better if the protocol didn't force everybody in the world to use the one protocol. We have different protocol stacks for a reason - they solve different sets of problems.

So let's say I make a post and bob_foobar@wordpress.com replies. The reply can't be seen on any ActivityPub implementations because he doesn't have an ActivityPub ID and inbox/outbox. So do we just drop it? That would be unfortunate and provides no transition strategy for those of us running federated software between multiple networks.

I'd propose we still send an actor object and the conversation element (activity) that actor created, giving whatever information we can provide - and let implementations decide if they can look up the actor and/or accept the comment. If they can't get an ActivityPub profile, many projects will probably just drop it. However those of us who are able to communicate with different protocol stacks could make an attempt to resolve the Actor some other way and show the full comment stream including bob's comment.

Any other options?