DotNetNuke is an open source framework for building websites quickly and easily. It is built on, and runs on Microsoft technology, and is extensible through the use of extensions known as modules, skins and providers. There is a whole ecosystem of websites that provide services and extensions for DNN, some free, some paid for. DNN is an extremely powerful tool when in the right hands, I could point you to a million sites built using the platform, but here's a cool one you might enjoy. http://www.indianmotorcycle.com/default.aspx

I started working on a book last August with a coworker of mine, Patrick Renner. In March/April we had everything finished up and the book was handed off to the production department to get squared away. Two weeks ago I received my first copies and the book started shipping out to vendors. The book is titled DotNetNuke 5 User's Guide, How to get your website up and running. http://bit.ly/dnnbook/

If you're looking for an easy way to learn how to use DotNetNuke be sure to check out our book. We wrote it to try to fill a gap in the DNN ecosystem, and to provide a good resource for people who are brand new to DNN and want to learn how to create a site and manage the content on that site. http://bit.ly/dnnbook/

You can purchase it from Amazon.com