I do use it

www.dashpoint.com and www.purdyplayground.org

it is an open source portal (based on an application known as IBuySpy) which was a sample application written during the .NET beta timeframe (I believe)

It has a quite large ecosystem surrounding it. People building custom modules, skins, etc.

If you want more overview information take a look at www.code-magazine.com duffy wrote a couple of good overview articles on the subject.

IMO it is best suited to small vanity sites where the developer doesnt want to spend time crafting a bunch of custom code.

Rodman