It is, only if Ning.com is, because this place (geeks.pirillo) is also http://livegeeks.ning.com , according to the page source . :)
According to the Ning.com "About" page, the Ning platform was launched in 2005. Drupal has been around since ~2001, so it could be built on that. In which case, Chris had a great idea, just a little later than the Ning folks (which include "Netscape" Marc Andreessen), but I would wager that even if Ning started on Drupal, it has evolved into something else quite different by now.
All of this was hasty, quick research - maybe someone who really knows will post at some point. Thanks for pointing out that blog post, Dejai!