That led to a thought experiment: What if the results had gotten out?

In that case, the Expedia survey did not get out; Mr. Barton’s assistant grabbed the document before anyone else. But Mr. Hohman and Mr. Barton ultimately decided it would not have been a bad thing if it had. While employee data, including salaries and workplace, are often hoarded by a tight circle of executives and officials in human resources departments, the men felt that the information would help the public make better career choices.

Not too long after, the two started Glassdoor. The website makes it easy for current and former employees of a company to review the good and bad of working there, rate the company’s leadership and reveal compensation information — all valuable information to job seekers and entertaining reading for the merely curious. The site now has more than 22 million members and has raised nearly $93 million. It plans to eventually go public, said Mr. Hohman, the company’s chief executive.

Not all of Mr. Barton’s ideas have panned out. King of the Web, a start-up he co-founded that ran a social media game which included cash prizes, shut down last year, for example.

Still, he has enjoyed a series of big paydays. Mr. Barton declined to discuss his net worth, but his shares in Zillow alone, where he remains executive chairman, are worth more than $400 million.

Despite his success, he has managed to maintain a relatively low profile. While he sits on the board of Netflix and has a role as a venture partner with Benchmark, a prominent venture capital firm, Mr. Barton is not as well-known as some members of tech’s “it” crowd. In part that is a conscious decision, as Mr. Barton has decided to live in Seattle to keep some distance from the hubbub of Silicon Valley.

“Personally, I like living here better,” said Mr. Barton, sitting in a restaurant near his office downtown. “People do other things. I can go to a soccer game, and I’m not standing with the co-founder of this and a venture capitalist at that.”

He arrived in Seattle in the 1990s to work at Microsoft, and wrote the original business plan for Expedia at Microsoft in 1994. Eventually, he yearned for more freedom when the company balked at spending large sums on advertising.