I find disruptive technology fascinating. 

So far in June, Opendoor has bought 37 houses, townhouses, and condos. This compares to 45 in the comparable period last month (May) and 37 in April. With 2253 deed transfers so far in Wake county in June, Opendoor transactions are statistically insignificant, unless, of course, you sell to them or buy from them. 

Opendoor holdings, by 6/1/2019 WCRE snapshot, shows they buy in a wide variety of property ages and sizes. 

As soon as Zillow buys a home through their Zillow Offers program, which to date they have not done in Wake county (per county records), I will post about the kind of properties they are buying. 

Upshots:

• For the time being, it seems to me Opendoor is not going away. As the largest brokerage (by sales volume) in Wake county at the moment, I see no reason why that would change. 
• They clearly acquire a wide range of property based on the historical facts
• They buy condos and townhouses as well as single family property.

Methodology: Put in dates and type (e.g. DEED) in your county recorder's indexed search (e.g. Wake) parameters, along with GRANTEE as Opendoor, and do your own query for your county. Use Opendoor as GRANTOR for determining SALES from Opendoor. Note they currently operate nationwide in a very limited geographic range of 20 +/- MSAs.

Disclosure: I have no affiliation with this company, just like I have no affiliation (6+ years ago) with American Homes for Rent in my other analysis and observations posts on BP. I do follow and analyze companies inventing and deploying disruptive technologies in industry groups where I have a financial interest, including real estate, (renewable) energy production, transportation, and agriculture.