这个人如何筹集了3100万美元的风险投资4YearsGreg Marsh unlocked the secret: Start with old-fashioned networking, then grow your own network.

When Greg Marsh moved to New York City, his wife kept locking herself out of their apartment. "Then she'd wait an hour for a locksmith to charge $150 for two minutes of work," he says. That got Marsh wondering about the locksmith industry -- which is $7.5 billion and totally fragmented.

He came up with an idea: KeyMe, an app that scans and stores digital copies of keys, which can then be printed at kiosks or ordered by mail. In just four years, he'd go on to raise $31 million of venture capital in three equity rounds. Here's how he did it.