Pinnacle Pctv Usb Question About Pinnacle Systems USB TV Tuner?

Question about Pinnacle Systems USB TV Tuner? - pinnacle pctv usb

Pinnacle Systems PCTV HD Pro Stick USB 2.0 TV Tuner

Apparently you can watch television on your desktop with this device, but how does it work? Do not subscribe to cable or satellite in the first place? Can I simply plug this thing in my computer, and suddenly get all these channels?