After a week of silly headlines, people would grasp the reality that actually its zero impact on life moving forward. It could well not be replaced with any other online anything, but rather a simple return to talking to people you know by other routes just like, well, 2 years ago.
You are conflating facebook and the internet. That traffic would NOT return to the mail service. Remember, there was email before facebook messaging. The phone services still have major SMS traffic and push notification systems like Apple's are used to announce FB activity.
I'm already finding my self moving away from FB towards dedicated services like Path, Instagram, and GMail. I'm starting to find myself using FB about once a week.
Digital sharing will never go away. But I wouldn't be surprised to see Facebook one day replaced by more interesting alternative(s).
People functioned perfectly well before Facebook and they will function perfectly well without it. Facebook is nothing more than a tool, one that I've never used and do not plan on using. As for the 800 million more people using their network, that number is way way way inflated. They might have that many registered users, but I doubt the active users is even a quarter of that.
Life will continue as nothing of value was lost...
As a side note, my GF is starting to complain about FB after being an avid user for years. 'My front page is full of ads for things I've liked'. The downhill (meteoric) decline is started when the normals start complaining.
On the contrary, when people complain it shows they see it as essential. They don't complain about non-essential online services; they just stop using them. I get excited whenever an OurDoings user sends me an email full of complaints.
But she's not complaining to FB, she's complaining to me and probably her friends. Word of mouth got FB started, and word of mouth will probably be it's death.
I complain every time there's traffic on the road I use to get to work. It doesn't mean I consider it essential that I make it to work in 6 minutes instead of 11. People complain about all kinds of inessential inconveniences.
When I say "service" I'm talking about the road. Getting to work is worth the inconvenience. That you complain instead of not driving on that road shows how much you value the road.
This site is a pain in the ass to pull up on an iPad. It scrolls strangely, makes the text too big, and generally results in a quick backpedal to the HN site.
After a week of silly headlines, people would grasp the reality that actually its zero impact on life moving forward. It could well not be replaced with any other online anything, but rather a simple return to talking to people you know by other routes just like, well, 2 years ago.