Hanselman does a whilrwind tour of the various popular web2.0 systems that have C# or .NET APIs.

In my book, this is all interop.

What makes it all possible?  First:  cool, interesting, programmable services.  I don't have high value scenarios for programming Picasa, or Twitter, but apparently somebody does.   And ... Second, .NET is interoperable.  It works with XML , with JSON, with HTTP and so on.  For those of you who have been using .NET for a while, this is no surprise. In fact it sounds inane to you, that I keep saying ".NET is interoperable" ;  But listen, it wasn't that long ago....

All the connections we're seeing these days are beautiful.