What is Kodi?
Kodi is just a media player. Anyone can head over to the Kodi website and download this sucker right now. It's also available in the Google Play store for Android devices. But you don't need an Android to use it -- the software runs on multiple operating systems (iOS, Android, Windows, Mac OS X, Linux) and can be downloaded onto computers, smartphones, and streaming boxes.
Here's the kicker: Kodi doesn't come pre-installed with any content. Think of it like browsing the app store for your smartphone; developers create an app, that app sounds good to you, and you download it. Similarly, developers create add-ons and content packages for Kodi that users download and install separately -- like recently aired TV shows, sports games, live events, podcasts, slideshows, and games. Browse the "Add-ons" section of the website and you'll see some of the usual suspects from your Apple TV or Roku, including NBC Sports Live, Twitch.tv, and YouTube, just to name a few.