Feature request: user interaction endpoints (or maybe filters)

[fields]

I'd like for the API to provide more visibility into user interactions. Ideally, this would include several new endpoints / filters:

1. A list of users who have responded to the selected user's posts (reply-to or mention).
2. A list of users who the selected user has responded to (reply-to or mention).
3. A way to request only posts (presumably stream) by users in either of the above criteria (this might be more generally a way to request a stream from arbitrary multiple users).
4. A way to filter the "posts created by a user" stream to show only responses or entirely exclude responses (and show only top-level posts).
5. A way to request only posts in threads that the selected user has participated in. (this has come up before; not sure what the status of that is)

[fields]

Per scruffyfox's comment, the general version of part 3 overlaps with #335

[fields]

Comments on "how would this affect clients" from the discussion in the developer's patter room copied here:

1-3 I would expect are two new lists - people I've responded to, people who have responded to me, and two new streams - posts from people who I've responded to, and posts from people who have responded to me

4 is a toggle switch on the existing user stream to show or hide responses

5 is a way to trigger notifications - someone has responded on a thread you were participating in

[ghost]

I would really, really like to have this in the API and I'm sure many other users would too. Because ADN is so conversational, mentions really fill up a timeline and I find that I have often missed the posts of those I follow as a result. I think that having this feature would really enhance the user experience. I hope you guys can consider it,

[gosorios]

Anna nails the reason to add this to the API. The Alpha experience gets terribly diminished when your app of choice loads 50 posts and almost all of them are conversations you were not following. Thanks.