Most of Zuckerberg's $13 billion net worth is based on an imaginary valuation of Facebook, apparently engineered by Goldmans. There's still plenty of opportunity for Facebook to disappear into obscurity, overshadowed by the next big thing, just like Myspace, Mixi, Friendster and Livejournal.
What you say can happen. Agree with you. My main peeve is with any such list in the first place - "actors who don't matter...", 'techie greats who don't matter' etc. etc. Makes me very angry, purely from basic human feelings POV.
And its obviously a link bait - '10 people who don't matter...' easily attracts people on to read (or just page visit) '50 people who do matter...'.
