Smart TV’s sell big globally, not so much in the U.S.

More than a fifth of all television sets sold in 2010 were smart TVs, according to the research firm DisplaySearch, which says the numbers signal that “a quiet revolution in TV viewing” is gaining a foothold.

How “quiet” the revolution is depends on whether you pay any attention at all to the media, which is rife with coverage of the rise of network-connected (and otherwise “smart”) televisions. But quiet or loud, DisplaySearch says the category will continue to grow at a fast clip – from 2.5 million sets on 2010 to more than 10 million in 2014.

Total TV shipments grew by a “staggering” 17 percent in 2010–to more than 247 million — representing “the best growth seen since the start of the flat panel TV transition,” DisplaySearch reported.

Sales in North America, however, were nearly flat as those screens, rising by just 0.4 percent through 2010’s first three quarters. Much of the growth came in Japan and in emerging markets. Part of the problem in North America (besides continued skittishness among recession-battered consumers) is that prices remain relatively lofty as features are added to TVs: LED backlights, 3D, Internet connectivity. Prices fell by 22 percent in 2009, compared with a drop of just 6 percent in 2010. LED-equipped sets will continue to increase their market share in 2011, rising to about a fifth of all sets sold as prices fall.

About half of all the sets sold worldwide were LCD TVs.

The “quiet revolution” could get a lot noisier once the market for smart TVs settles down and leaders emerge. For now, there is a baffling array of options, from simply buying an Internet-connectable set to buying a Google TV or Roku box to relying on Hulu, iTunes, or Netflix, or any number of combinations of those. Programmers, cable companies, and Internet upstarts are waging turf wars, the outcome of which is hard to predict.

Fortune’s Jessi Hempel writes today that there is great promise in the smart-TV world, but “for the moment, all that promise translates into a proliferation of new boxes and services that are impossible to compare.” For now, we have “a Web TV experience that feels a bit like the Internet circa 1998, before publishing companies embraced the Net and Google arrived to help us find and instantly consume the stuff we’re looking for.”