To Survive, Sometimes You Have to Let Go of Your Vision -- and Ego Entrepreneurship means exploring unknown paths, and sometimes that leads a founder somewhere different from where they started.

Glenn Kelman thought of himself as a software guy. He loves software. He co-founded a company called Plumtree Software. "When I applied for a passport or had to fill out my tax forms, I wrote down that I was a software entrepreneur," he says.

So when he became CEO of a real estate startup called Redfin, he had a natural direction: "I wanted to solve every real estate problem with software."

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