[axefrog]

I would imagine he's referring to the non-blocking IO and evented model. ASP.Net and friends use threads for everything, which allows for heavier processing, but also is more restrictive in terms of concurrency.

[tomkludy]

MVC 4 also allows non-blocking IO. Mark your controller as "async" and use async calls within your controller method.

The evented IO model is nice, but nothing earth shattering. Same can again be accomplished with async IO calls, which are trivially easy in .NET 4.5.