(FORTUNE Magazine) – Tony Fadell is happy to hand you his latest business card--senior director of music strategy at RealNetworks. But in his desk drawers you'll find old cards, from Philips, General Magic, Rocket Science, and two firms he founded, Constructive Instruments and ASIC Enterprises. He's 30.

Older generations might frown upon such rapid movement. My grandmother winces whenever I change jobs. (I'm 38, and I've worked at seven companies.) "Stop moving around! No one will want to hire you," she warns.

But this is Silicon Valley, where life whirls at the warp speed known as Internet time and there are more jobs than qualified people to fill them. There are no gold watches for loyalty, and your retirement plan is your stock. Rather than climb one corporate ladder, people skip rungs by changing gigs. Sometimes they start their own company. Ever since the "traitorous eight" (including Gordon Moore) left Shockley Semiconductor Laboratory to found Fairchild Semiconductor and pioneer the chip industry, Silicon Valley has been a breeding ground for people with startup ideas. Tracing the lineage of Valley luminaries, you find common roots: Stanford University (Jim Clark, Scott McNealy, Jerry Yang, Graham Spencer), Intel (John Doerr, Mike Markkula), Apple Computer (Steve Jobs, Steve Perlman, Marc Porat, Donna Dubinsky, Andy Hertzfeld, Mike Homer), and lately Netscape (Mike McCue, Atri Chatterjee).

The top breeders tend to be companies past their prime. When Apple was going nowhere, Steve Perlman fled and helped build two innovative startups, General Magic and WebTV (he eventually sold WebTV to Microsoft for $425 million). Silicon Graphics was a star for a while, but Jim Clark and Tom Jermoluk left to help build other companies. Netscapees who don't want to work at new parent AOL are founding companies now.

Past failures are no deterrent in this tight-knit community. Before rising to head Netscape's Netcenter Website, Mike Homer worked at ill-fated Go, a maker of pen-based computers that merged with Eo and was bought by AT&T before being embalmed. "Go failed," says Homer, "but we learned so much." Go's Stratton Sclavos heads Verisign; Randy Komisar has been "virtual CEO" to several Valley firms; Bill Campbell is Intuit's chairman. Not bad. "Where you've been has a lot to do with what you've learned," Homer says, "and with what you do now."

Our modest business-card proposal is designed for people like Homer--and for serial entrepreneurs like Jim Clark (Silicon Graphics, Netscape, Healtheon, and now myCFO) and Judy Estrin, Cisco's chief technical officer, who has formed three companies with her husband, Bill Carrico. The last was acquired by Cisco. "It's amazing how it all links back," Fadell says. "Your people knowledge is as important as your intellectual knowledge." He's right: In Silicon Valley, your value is a combination of where you work, whom you know, and where you've been. So we think it's time for some truth in advertising. We think it's time for people to start listing their corporate genealogies on the backs of their business cards.