Future of C#
Asynchronous programming
Writing asynchronous code in .net was always tedious. With this new feature it will be like writing synchronous code. Check samples in Visual Studio Async CTP.
Compiler Services
This feature was mentioned for first time in presentation from PDC08. As you can see, there is no Compiler Services in DEV10/.NET 4.0. It's because C# compiler is obviously written in C++. Anders said that for enabling CS the core of compiler must be rewritten to managed code. Will this affect the speed of compilation? We will see.
Note: As you can see in PDC10 code samples, there are many usings starting with "Roslyn". This is codename for C# managed code compiler.
Links
The Roslyn Project - Meet the Design Team
Mark Russinovich - Windows Azure - Mark mentioned C# 5.0, great interview
Visual Studio Async CTP
http://channel9.msdn.com/Blogs/Charles/Anders-Hejlsberg-Introducing-Async
PDC 2010: The Future of C# and Visual Basic
http://channel9.msdn.com/blogs/pdc2008/tl16
http://stackoverflow.com/questions/988623/when-c-compiler-is-written-in-c-will-one-be-able-to-modify-it
