What they allow you to do is download an app such as Netflix or HBO Go and watch all the movies and TV shows on those services without using a computer. All the Wi-Fi connectivity and processing power was in those boxes and gaming consoles, and they connected to your TV.
As such features became popular, television manufacturers began including that functionality directly in the TV sets. In the beginning, you would pay a little extra to have them built in, but the features are so common now it's become a standard inclusion in any new TV.
Whether you should get a separate set-top box such as a Roku or a whole new television with smart TV capabilities depends on a couple of things.
Do you already have an older TV you're happy with? If so, you can just buy a box such as a Roku, which runs between $50 and $100.
Do you already own a video-game console such as a PlayStation 3, Xbox 360, or one of the newer units such as the Xbox One or PlayStation 4? If so, they are capable of running some of the more popular apps such as Netflix, HBO Go and Amazon Instant Video.
Check if your Blu-ray or DVD player has the functionality built in. Only recent players say, 3 years old or newer will have the feature.
The biggest downside with either the gaming or disc-player option is it will have a limited number of apps it supports, certainly fewer than a Roku. But if you're just interested in Netflix and some of the others I've mentioned, perhaps that's good enough.
Another inexpensive option, especially if you have an Android-based smartphone or tablet or iPhone or iPad, is to get a Google Chromecast, a small dongle the size of a USB flash drive that you plug into one of your HDTV's HDMI plugs. It then can stream content such as Netflix or HBO Go from your mobile device to your TV. It's only $35. Again, the only problem is it supports a small number of apps.
The biggest advantage to getting a Roku box is that it supports hundreds of apps, including ones that show obscure content such as Kung Fu Theater, Cultorama TV, Retro Family Christmas and Manga. Those are just the official Roku channels, but there are hundreds more created by users that aren't on the Roku list.
If you're going to buy a new television anyway, it will be difficult to find one that isn't a smart TV. If you do find one that doesn't have the functionality, make sure it's at least $100 cheaper than one with it so you save a little money if you then buy a Roku or a similar box.
The main advantage to having a smart TV is it won't take up an HDMI port for an external set-top box, and you don't have a separate box hanging off the side of your TV. It's cleaner and less confusing if that functionality is built into the TV. The disadvantage is it won't have nearly as many channels and apps as a Roku.
But once you have that feature hooked up either way, you will open up a door to a whole new world of entertainment.
If you have a tech question for Vince, email him at email@example.com, and he'll try to answer it for his column in The Salt Lake Tribune or on its website. For an archive of past columns, go to www.sltrib.com/Topics/ohmytech.