Please, do not give facebook that much credit.
Facebook simply targeted the first real 'child' generation of computer users in their late teens early 20's with an social network medium to keep track of all their friends once they left high school and entered college. There is a reason it started out with college only students- they are the ones that had computer's as children, the money to already have been exposed and a desire to keep track of their friends once they moved away.
Absolute genius, and a little bit of luck, yes. But, the downfall of television, absolutely not.
Now, we haven't made computer's our TV's. WebTV failed- and I think one of the biggest reasons (aside from massive compatiblity issues with the web) is that our computer's are personal. We look at our e-mail, we write in journals, do work stuff, watch porn, etc. Its not nessisarily the stuff we want everyone to see.
Families don't get together to watch dad check his e-mail, but they do get together to watch a movie. TV has been less and less useful, with the internet able to provide video's, and removal of ads.
However, TV is still alive and kicking. The whole distribution system- ad driven phenomena has just moved over in different ways. Internet adds are prevalent in the same way TV adds are. But add blocker, firefox and general ignoring has made it a mindless sort of 'avoid the add' task. I use to do things during commercial breaks, but now I find myself trying to click away advertisements. Also, TV companies are catching on to the internet thing- they are offering shows online for free or subscription, and have their own ways to advertise. CNN does the stupid ad before the clip shows, and there are others out there to.
The TV industry hasn't figured out exactly how to move arched serial television to mesh and co-exist with computers successfully and profitably. But, they will find a way. I hardly think that the 30 minute reoccurring motion picture
is going to die any time soon.
Even if I don't own a tv.