'myspace' of the future

I'm required for my profession to get 40 hours per year of continuing education per year, and I sat through 16 of them in the past two days -- some classes helpful, some mind-numbingly dull, some somewhere in between but unmemorable.  The most interesting, but decidedly unhelpful, tidbit from a speaker today:  a prediction by know-it-alls in the social media industry that Facebook will be mostly gone in 5 years, replaced by something else.  Quick, sell your Facebook stock!