Shares of high-tech real estate brokerage Redfin surged on their first day of trading Friday. Initially offered for $15 per share, the company's stock had soared above $20 by early afternoon, valuing the company at more than $1.5 billion.

Founded in 2004, Redfin pioneered the concept of putting real estate listings on an interactive map alongside rivals Trulia and Zillow. But Redfin chose a different, more ambitious business model than its competitors. Zillow and Trulia make money by referring customers to independent real estate brokers. Redfin, in contrast, aimed to disrupt the real estate business by becoming a real estate brokerage itself.

"Real estate is by far the most screwed up industry in America," Redfin CEO Glenn Kelman said in a 2007 interview on 60 Minutes. "We feel like things that Amazon or eBay or Yahoo have done for other industries, we can do for the real estate industry."

In a traditional real estate transaction, the agent on each side of the deal gets a three percent commission. Redfin offered a do-it-yourself model where buyers would do more of the work themselves, lowering Redfin's costs and allowing it to pay thousands of dollars in rebates.

This approach sounded great in theory, but there was a big problem: customers hated it. Buying or selling a home is a complex, stressful, and often once-in-a-lifetime transaction. People wanted a personal agent who had plenty of time to understand their situation, answer questions, and guide them through the steps of the home-buying process. Redfin's early approach—with an ever-changing cast of agents showing homes and writing offers but not doing much else—left most customers unsatisfied.

So over the last decade, Redfin has shifted its business model to look a lot more like a conventional real estate brokerage. The company hired more agents in order to provide customers with personalized service. Today, Redfin buyers get a specific agent who works with them throughout the home-buying process.

To pay for those extra agents, Redfin has slashed its rebates. In 2007, buying a $500,000 home through Redfin got you a rebate around $10,000. Today, in Washington DC, the same home comes with a rebate of only $2,500. Redfin takes the other $12,500 of the three percent buyer-side commission.

Even with this extra revenue, Redfin has yet to turn a yearly profit. That's largely because the company is investing heavily in growth. Redfin has entered dozens of new markets in the last two years, and as a result, its revenue more than doubled between 2014 and 2016.

Still, it's safe to say that Redfin's effort to fundamentally disrupt the real estate industry hasn't come to fruition. The company's market share is about 0.5 percent, and it's around two percent even in markets where Redfin has been operating for a decade. The experience of buying a home through Redfin—I bought a home using the company in 2015—isn't dramatically different from the experience of using a traditional agent.

The company's stock is worth dramatically less than Zillow, the rival that chose to just focus on its website and leave the messy details of the real estate business to conventional realtors. As I write this, Redfin is worth around $1.6 billion, while Zillow, founded two years after Redfin, is worth $8 billion after acquiring Trulia in 2015.

"I can't walk around with a swagger and talk about destroying an industry," Kelman told me in 2015 interview.

Kelman said he was still optimistic about Redfin's ability to transform the real estate industry in the long run. He believed that some of the biggest opportunities for innovation were on the seller's side of the market, because sellers ultimately set the terms of real estate transactions. And because home sellers tend to be older and more risk-averse, it has taken longer for Redfin to build up a customer base on the seller's side of the market. In recent years, Redfin has experimented with 3-D home walkthroughs and has offered ultra-low one percent commissions to sellers in some markets.

Today, Redfin serves as a counter-example for the view that technology companies will inevitably disrupt old-fashioned industries. Redfin provides a valuable service, and it may drive further innovations in the real estate industry in the coming years. But there doesn't seem to be any danger that Redfin will do to real estate agents what Expedia did to travel agents or Amazon did to conventional booksellers.

Correction: This story has been updated to remove an inaccurate valuation for Trulia, which was acquired by Zillow in 2015.