This thing is pretty cool. When you connect it to your cable converter or satellite receiver and then to your Internet (it does have Wifi), it becomes a search engine for your TV. At any point while watching your TV, you can simply start typing the name of a movie, actor, director, etc. and it will display results from your channel lineups or even internet sites like Netflix, Youtube, and eventually Hulu. It works like Google, which is why they call it GoogleTV.
Here is a commercial for it.
http://www.youtube.com/watch?v=qyQb192-CPQ