When Google (GOOGL 0.69%) introduced a YouTube "guide" last year, it signaled a desire to make the service more like traditional television. Cook up a home screen with all your favorite programming in one place and you'll watch more, the theory went.

Smart move. While the number of original videos watched declined recently -- from 43.5 million last December to 37 million in October, comScore reports -- ad impressions rose sharply to 11 million from just 7 million over the same period, a 57% increase. More importantly, Google ranked second in October ad impressions after not even making comScore's list a year ago.

Meanwhile, Hulu, which had been first in December, dropped to third despite serving 59 ads per viewer -- up from 46. Not good news for corporate parents Comcast (CMCSA -0.33%), News Corp. (FOX), and Walt Disney (DIS -0.83%).

For its part, YouTube is hoping to build on its success by taking its "guide" to every device you own. The goal? Be your first choice for on-demand programming no matter where you happen to be.

Netflix (NFLX -0.62%) has already made strides in this area. More than half of users stream content from something other than a computer, Nielsen reports. Playing HD video on the go is getting easier.

Even so, Google's plan isn't without risks. In pitching channels, YouTube could blunt the need for search and thereby its appeal as a place to discover the new thing.

Yet that worst-case scenario could take years to manifest. In the meantime, South Korean performer PSY uploaded "Gangnam Style" to YouTube just four months ago only to see the video draw in more than 921 million views as of this writing. Think MTV would ever have generated that sort of global audience? Of course not.