And now: iBuyers, a.k.a. digital home buying companies. ATTOM Data Solutions is out with an infographic featuring the U.S. housing markets where iBuyers are present along with home prices data in those markets to illustrate how each market is fluctuating.

According to ATTOM Data Solutions Chief Technology Officer Todd Teta, iBuyers have been expanding at breakneck speeds. What started as a moonshot idea six years ago has now blossomed into a massive, billion-dollar home buying market in its own right — and it's not showing any signs of slowing.

Opendoor brought the idea to life in 2013, quickly followed by competitor Offerpad. Since then, countless others have hit the scene — including Redfin (via RedfinNow) and Zillow (via Instant Offers) and even brokerage- and market-specific ones like Door and Offerdepot.

But it's not just more players that are getting in on the game. There's also a footprint expansion happening, too. And though most of the major iBuyers got their start in the Phoenix area, this new-age home selling option has reached far beyond the borders of Arizona's biggest city.

By the looks of it, that reach is going even further as we head into 2019.

Regionally, the South has the most iBuyer action, with Phoenix essentially the epicenter of it all. Three players launched there (Opendoor, Offerpad and Offerdepot). Zillow's Instant Offers also now operates in the city.

Texas also has a big iBuyer presence. Dallas-Fort Worth, Austin, Houston and San Antonio all have at least one iBuyer in the market, and a few players have plans to expand further into the Lone Star State later this year.

North Carolina (specifically Raleigh and Charlotte), as well as Florida, California and Georgia also have decent iBuying activity as well. Atlanta is one of the few cities to have most of the big players in the market. Opendoor, Offerpad and Zillow are all on the ground in ATL.

For the most part, iBuyers are shying away from markets in the North and Northeast parts of the country. Housing affordability (and availability) likely plays a role in this, as does overall consistency of existing housing stock. iBuyers rely heavily on data and algorithms when evaluating potential properties. Areas with inconsistent and highly unique housing makes this approach less reliable (and less profitable.)