If you have Broadband in your house, and a wi fi router, you can connect your wi fi enabled TV to the internet and watch TV programs, films and so on via the internet (BBC iplayer for example).
For example I have a Sky box which has wi fi and I have connected it to my broadband router.
So on my Sky box I can go to "catch up" TV and download a program I may have missed or a film I want to watch.
Note if you do have broadband and it is limited to so much data per month then downloading a TV program or film is a lot of data so it can easily use up your monthly allowance.