Smart TVs are being hawked by every major manufacturer, from Samsung and Sony (NYSE:SNE) to LG, TCL, Panasonic and more. What constitutes "smart TV" means different things to different manufacturers, but the idea is to integrate passive television with interactive experiences, be it surfing the web, linking to an outside media library, or connecting to a home network.

"Second screen" television viewing -- watching from your couch with a smartphone or tablet in hand -- is already a reality for many of us. Yet taking this experience to the next level may may require a new set. Or at least that's what the thousands of exhibitors at last week's Consumer Electronics Show want you to think. Here's why they might have a point.

Look who's talking
At the opening keynote presentation, Qualcomm demonstrated how viewers of a Nascar race could choose to listen in on audio feeds from their favorite drivers, pull up stats, choose different viewing angles, and more.

Not sold? Fair enough -- so-called smart TVs have been around for a while. Maybe you'll be swayed by the prospect of ditching your remote control and simply speaking to your television. Over 750,000 televisions have already shipped with voice command technology powered by Nuance Communications, and Google recently added voice control to its Google TV platform.

There's also Apple (NASDAQ:AAPL) to consider. Thanks to an increasingly integrated viewing experience that includes major streaming channels Hulu and Netflix, plus YouTube for custom online programming, the Mac maker is proving itself a player in smart TV without actually having, you know, a TV.

The bigger picture
Would Apple adding a big screen to its product lineup get consumers buying again? Possibly, but we also might not need to wait. Ultra High-Definition, also known as UHD or 4K television (for its 4,000 pixels per square inch picture) turned heads at CES -- and rightfully so.

Ultra HD televisions uniformly offer a huge step up in viewing quality over mere 1080p screens. It's scarcely an exaggeration to say that the step from 1080p to 4K is almost as striking as the step from your old CRT set to your current television.

Sony, which two years ago was banking on 3-D become ubiquitous, has now gotten behind 4K with nearly the same fervor. A 56-inch Ultra HD prototype OLED screen, built in concert with AU Optronics drew crowds to the middle of Sony's booth.

While we were always skeptical about 3-D, 4K looks much more promising. It would be good news not only for set manufacturers and platform providers like Google and Nuance, but for a host of companies with enabling technologies.

A crystal-clear benefactor
Corning (NYSE:GLW), which introduced its latest Gorilla Glass product at CES, is just one that would stand to see huge gains from an upgrade cycle in televisions. Company representatives explained that the newer glass is not only stronger (and therefore can be used in even thinner, less-distorting sheets) but also very flexible. That may not be such a big deal for consumers, but it is a factor for manufacturers, which can literally roll glass out on the production line.

If there's bad news here, it's that we've tuned into this channel before. Two years ago, 3-D was the technology set to save TV; now 4K promises to do the same. Do we believe it? We're more convinced today than we were back then, but a dollop of Foolish skepticism probably isn't a bad idea -- even for cheery optimists like us.