Mark Zuckerberg is said by Forbes to be worth $2 billion, up $500 million from last year and equal to the lifetime earnings of around 2,000 of the Facebook founder's fellow non-college-graduates. What a difference six months makes.

Back in March, Zuckerberg dropped off Forbes' billionaire's list, presumably because the magazine cut its estimate of Facebook's valuation. In the interim, an Russian investment firms whose major backers include a scary Russian oligarch decided to invest in the social network. Suddenly, Zuckerberg is said to be worth even more. It's almost as tough his paper wealth, and that of his company, is subject to endless whimsical re-evaluations largely divorced from reality.