Can't really answer.
No: well, because I use it and it's a good way to make sure the folks are OK (read your fucking e-mails, big sis!)
Yes: the concept of having friends on there is crap anyway... just how many of your 500 friends do you honestly communicate with on a regular basis, huh?! I have 150, and only converse with about 40-50 of them.
But, even if it was shut down, some whip-smart fucker is going to start a new social networking site and in six months' time everyone will be raving about it and going 'Facewhat?'