I think Facebook will disappear, but it may take a bit longer than 3 years. Also, they won't completely disappear, they just won't be as used as they are today.

I think Facebook will disappear, but it may take a bit longer than 3 years. Also, they won't completely disappear, they just won't be as used as they are today. I think a lot of people are getting bored and frustrated with the service, but they have a lot of history on the site, and they don't have a better alternative to turn to. This causes the wrong form of user "loyalty:" they are trapped. It's hard to imagine a better service coming along, but they can eventually be outdone on the mobile front or their own internal inertia (which it seems they are fighting) will prevent them from being able to compete. Change happens fast. Something will show up overnight, then BOOM.. the end.