Per Wikipedia definition: A smart TV, which is also sometimes referred to as connected TV or hybrid TV, is the phrase used to describe a trend of integration of the Internet and Web 2.0 features into television sets and set-top boxes, as well as the technological convergence between computers and these television sets / set-top boxes. The devices have a higher focus on online interactive media, Internet TV, over-the-top content, as well as on-demand streaming media, and less focus on traditional broadcast media than traditional television sets and set-top boxes. Similar to how the Internet, Web widgets, and software applications are integrated in modern smartphones, the name "smart TV" is akin to "smart phone".
A smart TV device is usually a TV with integrated Internet capabilities, TV with 3rd party Android based dongle, or a external set-top box for television like DuneHD that offers more advanced computing ability and connectivity than a contemporary basic television set. Smart TV often allows the user to install and run more advanced applications or plugins/addons based on a specific platform. Smart TVs run complete operating system, usually embedded linux, or mobile operating system software providing a platform for application developers.
Smart TV platforms or middleware have a public Software development kit (SDK) and/or Native development kit (NDK) for apps so that third-party developers can develop applications for it, and an app store so that the end-users can install and uninstall apps themselves. The public SDK enables third-party companies and other interactive application developers to “write” applications once and see them run successfully on any device that supports the smart TV platform or middleware architecture which it was written for, no matter of who the hardware manufacturer is.
"Smart TV"s provide access to Internet-based services including traditional broadcast TV channels, catch-up services, video-on-demand, Electronic program guide, interactive advertising, personalisation, voting, games, social networking, and other multimedia applications