Alignment with Activity Streams #2
Description
Activity Streams (AS) is (as far as I understand) an abstract model and a vocabulary for describing activities that happened or may happen. It uses JSON-LD as the serialization.
During the last CG meeting (2025-12-02), @rigow asked about how we plan to align RDF Messages with AS.
The first part are the activity descriptions themselves. Our current version of the spec includes an AS message as the first example:
PREFIX as: <https://www.w3.org/ns/activitystreams#>
PREFIX ex: <http://example.org/>
ex:like-1 a as:Like ;
as:object ex:blogpost-1 ;
as:actor <https://pietercolpaert.be/#me> .In that sense, I would propose to treat Activity Streams as a potential future profile of RDF Messages – see #1. We could make a 1:1 correspondence, where an AS-profile RDF Message contains a single as:Activity (e.g., a like).
However, AS also defines collections, where we can list a series of activities in a single JSON-LD document, or in a paginated series of JSON-LD documents: https://www.w3.org/TR/activitystreams-core/#collections
This, to me, would be an implementation of an RDF Message Stream, specifically designed for the AS use case. That's permitted under RDF Messages, where we leave the door wide open to any shape or form of such streams. Note that this pagination mechanism is not that different from LDES, which we also consider as a potential future profile (see #1).
Summary
As I interpret it, Activity Streams is deliberately scoped-down to focus on JSON-LD serialization and serving a specific use case (social networks). It does not try to be as generic as RDF Messages. For example, in AS the message's structure and purpose and clearly defined – in RDF Messages they are not. Therefore, I do not see our work as conflicting with what was done in AS.
I propose to: (1) treat Activity Streams as a potential future profile of RDF Messages; (2) treat AS Collections as an implementation of RDF Message Streams.
I encourage you to share your views on this as well, as this is a very good case study that we could use to further inform our work.