"You know how Amazon has 'If you buy this book, you should also read these books?' We thought we were going to be that kind of a recommendation tool used on other sites to help people find stuff."

The company got its first push in January 2000, when a few angel investors, or wealthy individuals, loaned it enough money to start developing software. It was on its way, but there was still no clear moneymaking mechanism, and for years the company ran on faith and credit cards. After a while cofounders Glaser and Kraft decided they had to move on. Westergren stuck with the project and kept looking for investors.

"I had been pitching venture funds for a couple of years. I had pitched over 300 times to different venture firms. I didn't get a yes until 2004," Westergren said.

That was when Pandora.com was created, the Music Genome Project was plugged into personalized radio stations, ad space started selling, and revenue began to flow. It's also when Westergren's idea was paired with the shift the Internet has taken toward interactive marketing. Today Pandora has offices in Oakland, Los Angeles, Chicago, and New York and sells ads connected to sounds that consumers like — and therefore products to consumers. The field of interactive marketing is booming, and Westergren says anyone looking to break into Internet radio should first look into a background in advertising.

Then again, you could just follow his example: use your instincts and see what develops.

Tim Westergren is traveling the country promoting Pandora with town hall meetings. See blog.pandora.com/pandora for information.