Buddy, get a clue pls. What databindings in MVC?? C# 5 support for async is excellent (almost as good as F#), recently Python's Guido said he's gone copy that syntax to Python. I don't know what you mean by normaly, I use it everyday.
I know that you could some async stuff all the way back with 2.0, but I have never been fortunate enough to be on an enterprise project that uses it. As a result of that and watching questions on StackOverflow I didn't think that such development behavior was common.
There was async stuff in 1.0, but the really good stuff came with version 4.0 and 4.5. The Task Parallel Library is a very nice implementation of the Promise/Future pattern, that came from the functional programming world.
