John Doe, here. I'm a little pissed that you all talk about me like a piece of meat. I'm a human being. I'm so insulted I'm going to write a node app to do all of this in 12 minutes...
I fear for facebook long-term only because I can't imagine the things I said when I was 16 lingering around on my timeline forever. Fad or not, facebook's standing with teenagers today will not be a long-lasting one. High School you will eventually be abandoned by college you and then again by professional you. How will facebook synchronize with rites of passage? Maybe this is why the proponents of facebook are usually 30-somethings...already done morphing and, as such, don't get it.
John