With this release, they will start accepting external contributions to these products and will be running the project like other open source projects are.
Mono and the new Stacks
The mono module itself has now taken a dependency on this module, so the next time that you run autogen.sh in Mono, you will get a copy of the aspnetwebstack inside Mono.
As of today, we replaced our System.Json implementation (which was originally built for Moonlight) and replaced it with Microsoft's implementation.
Other libraries like Razor are next, as those are trivially imported into Mono. But ASP.NET MVC 4 itself will have to wait since it depends on extending our own core ASP.NET stack to add asynchronous support.
Our github copy will contain mostly changes to integrate the stack with Mono. If there are any changes worth integrating upstream, we will submit the code directly to Microsoft for inclusion. If you want to experiment with ASP.NET Web Stack, you should do this with your own work and work directly with the upstream maintainers.
Extending Mono's ASP.NET Engine
The new ASP.NET engine has been upgraded to support C# 5.0 asynchronous programming and this change will require a number of changes to the core ASP.NET.
We currently are not aware of anyone working on extending our ASP.NET core engine to add these features, but those of us in the Mono world would love to assist enthusiastic new developers of people that love async programming to bring these features to Mono.