Hi, I've been working on something a little similar to FEP-7888 which uses the context field as a grouping of a subjective context but more for discovery purposes than anything. For example, followers of a Service (I called it Topic in my doc, which I realize could be a little confusing now) used as the context field can use that to discover other instances that create content with the same context. Optionally, this can be decentralized by appending a nonauthoritative ID to the context, so the authoritative ID would be used for discovery only, and as a way to bootstrap federation.

Having context be completely authoritative (and thus, forcing an authoritative Collection as its representation) could be useful too, but it'd be great to have solution that allows it to be more ephemeral as well.