To answer mole:
DVR - Digital Video Recorder...same exact thing as Tivo, except different name.
It's for digital cable, and I don't know about cablevision. I have Time Warner.
Someone mentioned when does it know to cut out? You set it up by recording from the digital cable guide that comes with your digital cable package. So, if you don't have digital cable, there is basically a TV guide channel that is interactive and you can choose your shows. You just hit record there and it records. So, it basically just records the entire time block the show was given by the digital box. I've had it cut out a few minutes too early a few times, but that really only happens with HBO shows that run a bit too long (Curb, Sex, Sopranos).