I suspect that Facebook -- and its use -- will continue to change over the course of the next decade. Currently, it looks like the most promising technology for mass user interaction that has been developed.
StackOverflow is basically a high signal-to-noise ratio content farm. It sells the illusion of fame in exchange for generating content. There is no meaningful social aspect to it. I don't see any signs of it evolving over time, as it seems to exist for a very specific purpose.
Facebook is a mish-mash of previously existing communication technologies, mainly being presented to people who haven't used the prior forms extensively.
A chat system, a 'twitter' like system, a limited blog with comments system, photo sharing with comments, and the familiar followers/contacts that many site have these days.
While amazingly successful, I'd hesitate to call Facebook 'a technology'. They haven't pioneered much except for jamming all that stuff together for a very large audience..
Facebook is a mish-mash of previously existing communication technologies, mainly being presented to people who haven't used the prior forms extensively.
Alternatively: Facebook is a collection of wide-ranging social technologies combined in a tasteful, approachable manner, which has captured the interest of a wider range of the general public than anything before it, by a wide margin.
And will a Chinese student meet a German one and bah blah etc. on Facebook in 10 years? I guess we'll see whether it's even around in 10 years. My belief is that people will have moved on by then. 10 years is a long time and there's nothing particularly special about Facebook.
I invite you to reread my original comment on the subject, particularly the bit in parentheses. The point isn't that Facebook is the place where things will happen, but that all this seemingly inane social software focus will likely reap indirect benefits that are being ignored by the original author.
So, your prediction is that the greatest energy advances of this century will specifically come from two people in different countries who meet on the internet? It seems overly specific, yet also general enough to not be surprising. I'll go along with this.
StackOverflow is basically a high signal-to-noise ratio content farm. It sells the illusion of fame in exchange for generating content. There is no meaningful social aspect to it. I don't see any signs of it evolving over time, as it seems to exist for a very specific purpose.