We are looking into the possibilities of developing sites similar to iGoogle and BBC.  Specificilly the use of moveable modules/portlets or web parts (asp.net). In essence we want to give our enduser the capability of choosing which modules they want to display and where they want them to be displayed.

I have struggled to find any information/samples on any implementations like this with DNN. I did find an old article at http://www.ventrian.com/Resources/Blo... which points back to a couple of DNN Blog posts but they are not longer listed.

Are any reasons (pros & cons) to not build this kind of interaction with DNN?

Any help or insight appreciated.

You can definitely give users the ability to add modules (Webparts in SharePoint = Modules in DNN) and allow them to add them wherever they want on the page. This can easily be done via Drag & Drop. I just cut a video demoing how this is done.

Check it out here: Drag & Drop Modules in DotNetNuke

Ok here's a quick screencast that may fit your needs...

In this scenario I have a user named "Tracey" who is in the "Marketing" security role. I gave that permissions role the ability "Add Content" (ie modules) to the page so she does have that ability but this also allows her to move the modules around on the page. 

Take a look -- http://screencast.com/t/x1EkyWcL