Facebook's sinking stock shares have cost Mark Zuckerberg some bragging rights among his tech peers. As unfathomable as it might seem to ordinary folks, Zuckerberg's worth dropped by $423 million yesterday, reports Bloomberg. His fortune is now figured to be $10.2 billion, about $400 million less than James Gooodnight, co-founder of software maker SAS Institute. The slip means Zuck is now out of the top 10 list of the richest tech titans, with Goodnight taking his place. (No. 1 is Bill Gates, at $62 billion.)