Nobody watches live tv anymore. Well, I guess people do since every time I call the cable company about a problem with my dvr box, they ask if I have the same problem viewing live tv. So if this is a diagnostic question, it must still be common for people to do that. Personally, I can't imagine doing that unless there's something pretty engaging on my computer screen.
Side note, my cable company uses virtual dvr's where all the recordings are on their servers. So playback of whatever you record is really being streamed to you. It's a great concept except they still haven't worked out all of the bugs.