[return0]

The vast majority may be useless, but a significant minority are valuable (e.g. maybe ~ 10% in HN). Why throw away that value?

[rubidium]

Because right now we have a system that works. Email the author. I've ALWAYS gotten a response.

[arcanus]

I think email (private communication) will always be useful.

However, some general questions being publicly available would be also arguably have utility.

[curt15]

There are already established forums for discussions, like mathoverflow.

[nl]

Why throw away that value?

Because others can extremely negative - to the point where they may put some people off publishing in open forums.

The very small amount of value that they may add is easy outweighted by a single person not publishing.

[return0]

I do not believe that. On the other hand not all publishing is valuable: http://www.nature.com/news/the-pressure-to-publish-pushes-do...