Defining the neighborhood as the area north of Spring Road and Rock Creek Church Rd and south of roughly Emerson Street, the average flip netted $312,000, more than anywhere else in the country. (They define a flip as selling a house less than 12 months after buying it.) Other neighborhoods in the city make the top 20 too, with Brookland coming in 3rd and Ft. Totten and Stadium/Armory at 6th and 7th.
This could imply a superheated housing market, or people wanting to make a quick buck. Good for the sellers, I suppose, but maybe not good for anybody who wants to live there.
It's not all bad news though -- the site does report that total flips are down since 2012, and Columbia Heights, interestingly, isn't on the list. Maybe house prices are high enough that flipping doesn't result in that much gain.