A “smart” tv is one capable of accessing the internet so you can browse the web etc from your armchair on the tube, rather than having to go to the ‘puter. It’s pretty neat.
I like ChromeCast, because you can use an Android/iPhone/iPad/Laptop for the remote, to watch Netflix and YouTube videos, and it’s easy to hook up.
As of now the choices are a bit limited, but there should be more apps for it fairly soon.