Private inner classes in C# – why aren’t they used more often?

I am relatively new to C# and each time I begin to work on a C# project (I only worked on nearly mature projects in C#) I wonder why there are no inner classes?

Maybe I don’t understand their goal. To me, inner classes — at least private inner classes — look a lot like “inner procedures” in Pascal / Modula-2 / Ada : they allow to break down a main class in smaller parts in order to ease the understanding.

Example : here is what is see most of the time :

public class ClassA
{
   public MethodA()
   {
      <some code>
      myObjectClassB.DoSomething(); // ClassB is only used by ClassA
      <some code>
   }
}

public class ClassB
{
   public DoSomething()
   {
   }
}

Since ClassB will be used (at least for a while) only by ClassA, my guess is that this code would be better expressed as follow :

   public class ClassA
   {
      public MethodA()
      {
         <some code>
         myObjectClassB.DoSomething(); // Class B is only usable by ClassA
         <some code>
      }

      private class ClassB
      {
         public DoSomething()
         {
         }
      }
   }

I would be glad to hear from you on this subject – Am I right?

How to make Collapsible comment box like Stackoverflow

I am building a site and I have a list of status updates and I want to allow the users to write comments for each of of the items in the list

However I am trying to implement a UI similar to the way stack overflow works
specifically the collapsible comment form / list where a user clicks on add comment on the specific status update in the list, and below that item in the list the comment entry form shows up along with the specific comments already posted.

How do I accomplish this using Jquery?

Note: looking also for the markup example another words a working sample. Thanks
And yes if you could show Async postback that would be nice too