Clarify namespace

[sslavic]

1. Does namespace identify event or event source (producer)?
2. If latter, what is the value namespace adds on top of source-id?
3. Is there a use case where events with same (event-type, event-type-version) can be published by more than one event source, so with difference in at least one of (source-id, source-type)?
4. If namespace identifies event source and there's value added of namespace on top of source-id would it make sense to include namespace together with (source-id, source-type) as property of source object?

[deissnerk]

In yesterday's call the need for specific examples was mentioned several times. Do we have an issue that captures this? Is it part of #37 ? I think it also affects #58 and probably many others.

[duglin]

if by example you mean "use cases driving our work", then yea I think #37 is part of it, but also the use-cases.md file that @ac360 recently added should cover it too - and PRs are welcome to add more. We should probably make sure we don't duplicate stuff between those two things (too much).

[duglin]

Can we pull this one into the overall "what is the source?" discussions? It seems related to me since they're all about identifying where the event came from so it makes sense to tackle them all at the same time.

[ultrasaurus]

I think this is addressed by: #123