Although stairways dominate the scene, the subject is the newsstand. It seems the photographer has asked passersby to clear the area in front of the stand so that he could get a clear shot of it.
The presence of the hackney cab and the dress of pedestrians indicates that we're in a relatively upscale location and, indeed, a little sleuthing shows this to be 6th Avenue El at 23rd Street. The El station is the nearest high-speed transit service to destinations that were popular with middle-class and even upper class New Yorkers: The theater district was a block to the west and extended a bit northward as well. Posh blocks of 5th Avenue at its intersection with Broadway lay a block to the east. There, as well, one found a lovely park called Madison Square. The Flatiron Building had just been completed where 5th, Broadway, and 23rd came together.
The Masonic Hall (1875), home of New York Masons, is at the photographer's left elbow. Next to it: the Horner Furniture store (Robert J. Horner's, 1876-1912). Across the street: McCreery's dry goods store on the site where the Edwin Booth Theater formerly stood.
If the people we see descending continue along the sidewalk, they will soon pass the Eden Musee, about half a block away on the north side of 23rd. Some may be headed there; others to the many merchants on this block, including the great Stern Brothers dry goods store just across the street from the Musee. Best & Co. stood next to Stern's (1895-1907) and Bonwit & Teller's next to it (1898-1911).
Here are some details from the photo.
1. The poster at the foot of the stairs is an ad for Hunter Baltimore Rye whiskey ("The First Over The Bars").
2. Knox's Gelatin was heavily advertised in New York at the time. The ads frequently featured white and African-American cooks, as here. I've given a print ad that's closely related to this display in a footnote.
3. Malta Vita was a grain product marketed as a restorative. It was a combination of whole wheat and malt extract. A print ad of this period says it could be used for "renovating your system and cleansing the blood of all impurities."
4. New York's elevated railway system was blessed with some decorative wrought iron.
5. The artistic freedom of the iron work contrasts unfavorably with the highly utilitarian gum machine.
6. Click the image to see the enlarged version. You'll notice the wide variety of magazines on sale. You can find some of these covers on the web. I've given a few in the footnote.
8. This is a reproduction of a painting called "All That Was Left of Them." It shows the last-ditch battle of a British cavalry unit, the 17th Lancers, against Boer guerrillas in September 1901.
This detail from a fire insurance map of 1899 shows the location of the photographer. Click image to view full size.
Here's the full sheet from which I took the detail.
This print of a drawing called Snow on the 'El' by Martin Lewis shows the same stairway and newsstand three decades later. A reader of the Shorpy blog owns the print and another reader found an entry for it in a catalog raisonné of the artist.
23rd Street (Manhattan) in wikipedia
New York Songlines: 23rd Street
Stern's in wikipedia
The Castro Building
A patent: Lanahan & Son, William, Baltimore, Md. "The First Over the Bars, Hunter Baltimore Rye."(For Whisky) - Annual report of the Commissioner of Patents, United States. Patent Office (U.S. Govt. Print. Off., 1903)
History of Knox Gelatin
Read All About It: 1903 (Shorpy)
 I've done quite a few others. You'll find them under the Detroit Publishing Co. link in the "Labels" list in the right-hand panel of this page.
 The sleuthing was done back in December 2009 by a reader of the Shorpy blog who uses the name jsmakbkr. I've previously written about this area. See Eden Musee, further east on 23rd, see the posts on the Flatiron Building and Madison Square.
 Charles Knox, who began manufacturing the gelatin in 1900, was a firm believer in the power of advertising. His ads were highly inventive as well as ubiquitous as this example shows: "During the William Jennings Bryan - William McKinley presidential campaign of 1900, Charles Knox got permission from the Commissioner of Highways to hang fifteen political banners over the streets of New York with the words "Hopes to Win" under each candidate, and across the top: "Knox's Gelatine Always Wins." City officials were irate, but Knox had the permit to hang the banners and declined to remove them. The story, of course, made every newspaper in the state and led to Charles Knox becoming known as "the Napoleon of Advertising." -- History of Knox Gelatin
 The current manufacturer has made a history page for Knox Gelatin.
 Here's the source of the Malta Vita quote:
And here is the page of the Woman's Home Companion from which it comes (March 1903).
source: Harvard University Library
This ad comes from Cosmopolitan, November 1902.
 These images of magazine covers come from magazineart.org.
These images were uploaded by people who left comments when the "newstand" image appeared on the Shorpy blog.
 Here are links to the comments left by the two Shorpy readers: The owner of the print: Anonymous Tipster and the person who found the entry in the book, "The Prints of Martin Lewis, A Catalogue Raisonne": LilyPondLane.