The two titans of online real estate plan to join forces, meaning that overnight they’ll literally own the world of real estate data.

Zillow, Inc.’s planned acquisition of Trulia, Inc., which was announced earlier this week as a $3.5 billion stock deal, means that for the first time the online real estate world will be dominated by a single player. The two websites together account for 71 percent of all traffic to real estate websites, according to ComScore data.

Not only does the deal mean Zillow and Trulia will become true ‘household’ names, but in the long term the combined entity could transform the real estate industry as we know it. The two firm’s datasets will create an enormous database of real estate listings and related information that no one else can match.

The two brands will continue to remain distinct from one another, at least for now. Part of the reason for this is because, surprisingly, there’s not that much of an audience overlap. Half of Trulia’s users never visit Zillow, while two thirds of Zillow’s users don’t bother with Trulia.

That’s all the more surprising when you consider that both sites offer essentially the same service. Both cater to buyers and sellers, and both try to produce as many listings as they can. There are some differences though – for example Zillow is popular for its “Zestimates” feature that estimates the market value of over 100 million homes on its database, while Trulia is better known for its fancy visualizations like heat maps of commute times and crime rates.

The Google of home search

Speaking to the New York Times, Zillow CEO Spencer Rascoff said the plan is to create a portfolio of real estate websites under a single corporate banner, similar to the what InterActiveCorp (IAC) and Expedia, Inc. have done in online dating and travel, respectively (Rascoff was co-founder of Hotwire, a travel services company that’s now owned by Expedia). Zillow plane to integrate Trulia’s data with its own to establish itself as the country’s most comprehensive home listings’ database.

What has the market abuzz, however, are the opportunities to combine, massage and sell cuts of the data to everyone from contractors to investors. Real estate transactions often portend broader economic trends that can yield lucrative profits in other ways. Real estate blogger Rob Hahn (Notorious R.O.B.) wrote that one of Trulia’s best assets is its infrastructure for “ingesting, processing and distributing listings”, which is far better than Zillow’s.

Calling the combined companies a new “platform for listings distribution to the industry,” Hahn wrote, “The new Zulia can offer a major benefit to the industry in terms of listings: send one feed to one company, and Zulia can make sure it goes where it needs to go, deliver huge consumer audience, and deliver top-notch detailed reporting.”

By acquiring more data, Zillow stands to improve its “Zestimates” feature to make it kind of a Google for home values. The company will also be better able to personalize recommendations based on their previous search histories.

Smarter homes, smarter data?

But the potential grows far bigger as people’s homes become smarter. Writing in Forbes, Adam Ozimek pointed out the potential of combining data from smart devices with real estate and demographic information to deliver greater insights to buyers and investors.

“Robot vacuums will know the dimension of every room in the house, the kind of flooring in each, and maybe even the quality and age of the flooring; smart TVs will know which room is the living room; Nest knows which room is the kitchen, which are the bedrooms, and how energy efficient the home is,” he wrote.  Ultimately, this could lead to the creation of extremely high-dimension datasets that offer a far more detailed view of a home and its valuation than what’s currently available.

“The power of smart data and analytics will make real difference in real estate,” said Nitin Shingate, CEO and co-founder of RentalRoost, Inc. “The value of data explodes when it can be linked with other data; thus integration is a major creator of value.”

That’s not to say all of Zillow’s and Trulia’s data is perfect. Both companies have been criticized in the past for inaccurate and incomplete listings. Combining datasets should also address some of these inaccuracies.

“There are some unique advantages to operating two websites with a wide array of data, and they can feed data back and forth from one another, so their individual data quality should go up,” said Vikram Raghavan, co-founder of RentalRoost. “As far as feasibility is concerned, real estate data is fairly simplistic and it shouldn’t be too hard to merge datasets.”

Zillow and Trulia’s databases are already incredibly useful tools for anyone who’s in the market to buy or sell a home. And by merging into one, vastly bigger and more accurate database, they’ll soon become indispensible.