In the case of this article, I think the writer has (wrongly) assumed that people know about Hine, using photography for social purposes. (hence the links I added)
It's often said that Hine created the foundations for the social documentary photographic tradition in America, although Riis with How the other half lives in the 1890's would have had a big influence at the time.
It's an interesting subject. Obviously for the British side, you've Bill Brandt, Chris Killip, the Exit Group. I read Nick Danzigers books, with one where he travelled around Britains deprived areas. There's so many when you start reading into this genre.