STARS OF SILICON VALLEY

Facebook: Mark Zuckerberg (1984-)

Personal fortune: $14.7billion

University: Dropped out from Harvard

As a young student at Harvard, Zuckerberg was approached by Cameron and Tayler Winklwvoss, who wanted him to write the software for a new social website called Harvard Connection.

Since Facebook, which Zuckerberg subsequently created, was a very similar concept, the Winklevoss brothers have always maintained he stole the idea. This year, Facebook was floated on the stock exchange. It was valued at $108 bililon, briefly making Zuckerberg the youngest man in Forbes' list of the world's 40 richest people. The flotation became a fiasco as the company's valuation fell by $29 billion as investors realized the price had been exaggerated.

Apple: Steve Jobs (1995-2011)

Personal fortune: $8.3 billion

University: Dropped out of Reed College, Oregon

Steve Jobs co-funded the Apple Computer Company in his adoptive parents' garage in 1976. Although Apples were always seen as easier to use than other computers, PCs were much cheaper and by 1985 he was fired from hi sown company. Apple continued to decline, buy Jobs did well thanks to his possession of Pixar Studios, the makers of Toy Story. 

In 1996, Jobs returned to Apple, beginning its remarkable recovery. Guided by his obsession with good desing, the company produced a series of hit consumer products from 2000 onwards. By the time of his death, it had become the most valuable company in the world. The company is now led by Tim Cook, and desing remains under the control of Sir Jonathan Ive, the British designer responsible for the iMac, the iPod, the iPhone and the iPad.