What is Documentary Photography?

Black Tap Magazine has a helpful article that distinguishes between photojournalism, documentary photography, and street photography. I found it particularly helpful to see the author grapple with the differences (and commonalities) between documentary and street photography, with the former focusing more on projects and potentially posed/non-urban photography, and the latter being cast as more spontaneous and less project-driven. While I think good street photography should be emotive and tell a story over time, I appreciate that the core assertion is that documentary photography must tell (or try to tell) some story, often as a photo set, whereas street photography is not similarly bound by these conditions.