A mega-mansion in the Bel-Air foothills is already sold for $75 million.

The buyer hails from mainland China and, according to Variety, the buyer paid in cash and is a Chinese billionaire businessman, who managed to track down the home through the online real estate database Zillow. He also used the app to contact the listing agents for a tour of his soon-to-be property.

Urban legends traced the buyer's story of finding the property on Zillow and contacting his agent through the app, after which he bought the property using his checkbook.

But in the real world, it is rare for billionaires to find their dream homes listed on Zillow and any other real estate app. These buyers usually have a team of attorneys and assistants to find these real estate developers and contact them.

If it is true, it's a testament to how huge the digital evolution going on in real estate is. These buyers are usually very discreet about buying these properties and the proceedings are normally dull ones.

The identity of the buyer is left to speculation as of this moment. Most of the rumors point to Liang "Johnson" Zhang, the son of Zhang Li, a Chinese mining and real estate tycoon worth $3.2 billion, according to a list of the richest persons in the world.

A closer look at Zillow reveals how Rich Barton brought it into the world on December 2004 as a digital solution that would "revolutionize" real estate.

It didn't happen as soon as he would like, Forbes reported, and Zillow appeared as if it was going nowhere. Google Maps changed their fortune as they worked closely with the satellite data it bounced.

It has a $9.5 billion market cap to this day and Rich Barton's stake in the once-troubled company is worth $700 million. It has come a long way from 2004 and now, it is reportedly instrumental in helping the younger Zhang finding his $75 million-worth dream house.

Zillow became bigger this year because even home buying has become digital. In essence, Barton was looking into the future all those years ago. His belief that technology and tech entrepreneurs along with it would change the face of real estate paid off.

Zillow and buyers like Zhang are a match made in heaven, perhaps. Zhang is no stranger to big payoffs. Earlier this year, he reportedly paid about $39.5 million for a massive hilltop villa in Portofino, near the Italian Riviera. That he would look for these luxury properties on apps like Zillow could be the evolution of real estate buying.