Just to clarify a couple of points in this thread.

1.  DotNetNuke Corp does not create and sell documentation.  We have documentation that is freely available in many different forms right here on DotNetNuke.com.  Because of the sheer volume of documentation it is not always kept in sync with the codebase.  We make an effort every year or so to go back and revisit old documentation.

2.  Some companies and individuals make books, ebooks, videos and articles available to help fill in some of the holes left by the core documentation.  In a few cases, these individuals and companies have provided access to a few of these items for distribution here on DotNetNuke.com in a limited format.  For example, all of our online help is provided at http://www.dotnetnuke.com/Resources/Knowledge/DotNetNukeOnlineHelp/tabid/787/Default.aspx. If you prefer to have this available offline then you can purchase the ebook from the author in the Marketplace.  This content is not owned by DNN or DotNetNuke Corp. but is graciously provided by the author for our use here.

3.  There is an effort underway to consolidate all of our free documentation, including some blogs, selected forum posts and the more traditional pdfs and word documents in one central repository to make it easier to find and easier to maintain.  This effort is just starting to get its legs underneath it and we should be seeing the fruits of this effort over the next couple of months as documents are converted into a common format for editing and display.

it would be great, if PowerDNN will contribute their documentation to the new documentation section to make those stuff available to all users.

I have already given my permission to use all the content from http://www.adefwebserver.com/DotNetNukeHELP/ on the new Core site. There is a bunch of DNN stuff on sites all over the Internet and I would hope that others will realize that participating with the Core repository will help everyone including exposure for their own sites.