Last week, Walt Mossberg and I interviewed entrepreneur, high-definition television fanboy, dancing fool and reliable gadfly Mark Cuban at the seventh D: All Things Digital conference.

Cuban, who sold his start-up Broadcast.com to Yahoo (YHOO) at the peak of the Web 1.0 bubble for billions, has been using that haul to do a lot of stuff.

In September 2001, the innovative Cuban launched HDNet, a provider of high-definition news, entertainment and sports programming. In January of 2000, he also used all those bucks to buy the Dallas Mavericks NBA franchise. He’s also co-owner of Landmark Theaters, Magnolia Pictures, and Rysher Entertainment, and holds a stake in Lions Gate Entertainment.

Cuban also made a laudable effort on the television dance competition, “Dancing With the Stars.”

After our onstage interview (highlights of that video are also below), BoomTown also got him to be more specific about his thoughts on a variety of things he discussed, including Google (GOOG) and its underwriting of its YouTube video subsidiary, HD TV, the problems with broadband and the Internet as a “utility.”

(And don’t miss his cheeky new post on his Blog Maverick site–“Who Cares What People Write?”–about ignoring, well, what some “amateur outtie” bloggers say most of the time.)

Cuban in the Green Room at D7: