Silicon Valley is rife with entrepreneurs who have been through multiple business ventures in search of a big pay off. For Chad Hurley and Steven Chen, still both in their 20s, it took only two shots.

Mr Hurley, who trained as a graphic designer at Indiana University of Pennsylvania, and Mr Chen, a computer scientist from the University of Illinois, got their first taste of the dotcom life as early employees at PayPal, which went on to become the largest online payments company.

As only the 15th employee, Mr Hurley was hired to design PayPal’s logo and its user interface. More recently, as chief executive officer of YouTube, he has quickly had to master much broader business skills, overseeing YouTube’s rapid expansion and leading negotiations with established media concerns and potential advertisers as the company searches for a solid business model to cap its early audience success.

Mr Chen, by comparison, has stayed further in the background, taking charge as chief technology officer of a technology platform that now serves up more than 100m short video streams a day.

EBay’s purchase of PayPal four years ago unleashed Mr Hurley and Mr Chen, along with a group of other option-rich executives, to start the search for their next big online opportunity. That group included Roelof Botha, PayPal’s former chief financial officer, who became a partner at Sequoia Capital, the Silicon Valley venture capital firm that had scored earlier dotcom hits with Google, Yahoo and PayPal itself. Thanks partly to the earlier personal connection, Sequoia has been YouTube’s only venture capital backer, and Botha now sits on YouTube’s board.

Like Mr Hurley, Mr Chen and Botha, other former PayPal executives are also now playing a leading role in “Web 2.0”, the latest manifestation of online mania in Silicon Valley. They include Reid Hoffman, founder of professional social networking site LinkedIn, who is also an investor in a range of other web start-ups; Peter Thiel, who amongst other things was an early investor in Facebook; and Max Levchin, founder of Slide, on online photo site.

The connection with former PayPal colleagues reaches beyond the dotcom sphere. Mr Hurley was an investor last year in Thank You For Smoking, a hit movie whose executive producers included Thiel, Levchin and other former associates.

Mr Hurley and Mr Chen, however, have been the first to hit the big time. After little more than 18 months their early success has now grown to outshine PayPal itself, for which eBay paid $1.4bn.