[messaging] Minimal requirements for group chat

[Ben Laurie]

On 17 April 2014 21:25, Joseph Bonneau <jbonneau at gmail.com> wrote:
> To try to summarize this thread so far, Michael proposed paring down
> requirements slightly, specifically allowing O(N^2) communication for each
> message and collision-resolution semantics, with the goal of keeping the
> protocol simple. Kurt suggests that the requirement of having a consistent
> total ordering on messages for everybody is the hardest goal left. Ximin
> suggests partial ordering with flags to indicate partial ordering to users.
> Moxie suggest that we can already do this with a simple protocol but the UI
> (threaded messages) is then too complicated for a small screen (Tom later
> provided some nice examples).
>
> There appears to be a tension between UI from protocol complexity here. We
> can imagine designing a simple protocol that requires a baroque UI with
> messages threading and rejoining, or a very complicated protocol that allows
> a simple UI (linearized messages).
>
> Personally I'd lean towards the latter approach. This seems to be what
> Michael's original thinking was, admitting a lot of messages and some
> latency to allow for a simpler UI in the end. Though it's definitely worth
> trying to design both cases, or consider if there's anything in the middle.

Causal ordering.