WCF uses .net 2.0 CLR!

trying to activate WCF on my IIS7, I spent a lot of time trying to get .net 3.5 option on the application tool, at the end I discovered that my logical reasoning is useless, here is the answer :

A question that comes up a lot is this: How do I tell my IIS Application or Virtual Directory to use ASP.NET 3.5 rather than ASP.NET 2.0?

Folks often go into the IIS6 or IIS7 manager and setup an AppPool and see a properties dialog like this, and when the pull down the option, they often expect to see .NET 3.0 and .NET 3.5 in the list and it's not there, and they freak out, rightfully so.



...

Basically, remember Framework version != CLR Version. If you configured an IIS Application to use .NET 2.0, you're talking about the 2.0 CLR. WCF Applications use the .NET 2.0 CLR with the new 3.0 WCF libraries.

* .NET Framework 1.x = CLR 1.x
* .NET Framework 2.0 = CLR 2.0
* .NET Framework 3.0 = CLR 2.0
* .NET Framework 3.5 = CLR 2.0 + (C# 3.0 | VB9)

from Scott's blog