tv to pc question

i've come across some sites that offer tv through your computer. it gives you the program plus the code or login info to set it up everything.

what i would like to know is if they can trace me using it? what i can do to avoid detection if its possable.

has anyone used one and how well do they work? can you really pick up alot of good stuff. i mean like movies and such.

thanks and happy holidays.