There are several interesting factoids in the most recent TV universe data from Nielsen, but the one that caught my attention in light of the new season beginning is this: U.S. DVR penetration as of July 2010, 37.3 percent.

Now, if you travel in certain circles, that might seem awfully low. But it’s up almost 50% from two years earlier, reflecting gradual but steady growth — and continued hurdles for ad-supported television to clear.

On the plus side, all those DVR households don’t have to make really tough choices about this or that in a given timeslot. But they will be time-shifting programs, which has become a real problem for all those new 10 p.m. dramas trying to establish a toehold.

The other amazing thing, given how long TiVo has been around and how many of us have come to rely on the little fellow, is this: In January 2006, DVR penetration stood at a mere 1.2 percent.

In essence, the devices have gone from nowhere to nearly two in five homes in less than five years. And for many of us, they’re used so frequently it’s difficult to remember back to when we didn’t have them and actually had to use VCRs to record programs.

Remarkably how fast technology is changing and reshaping playing fields these days.