In the discussion of "editorial" versus "commercial" usage, editorial refers to licensing an image to accompany an article, or for use in a textbook, that kind of thing, as opposed to using it to promote or sell something, like a brochure or food package.
"editorial" licensed images do not normally require model releases, due to the nature of their use. ie, a crowd at a baseball game accompanying an article on baseball, or a picture of Obama on Time magazine. It is also a way for people who are into "street" or "grab" photography to sell their images, since it doesn't require permission from the subjects. However, that is a slippery place to tread.