Cool Diagrams - What software is being used here?

I've seen some cool, nifty data diagrams done on some blogs/articles and have been wondering what software they were using to render these diagrams, e.g. MS Visio? For example, what is used on this blog to create those colorful diagrams towards the middle of the article under "Definition Providers": http://www.thecodejunkie.com/2009/05/introduction-to-mef-programming-models.html?

I find these diagrams very appealing...

[EDIT - Addition]: I run across these diagrams all over the place, e.g. one of the bloggers I follow is Nikhil Kothari - http://www.nikhilk.net/Silverlight-Layout-Panels-1.aspx.

It's from Office 2007, for sure. They can be created in Word, Excel and Powerpoint 2007.

Office has a tutorial to create what they call a "SmartArt Graphic"

_{(source: java2s.com)}

Here is a home made picture, from Word 2007 :)

Now with matching colors!