Speaking of critical mass/agglomeration

Newsstand at 2nd Avenue and 67th Street in NYC. Photo by Rachel Barrett, from the New York Times.

Understanding cities requires some understanding of urban economics, which is something that Ryan Avent writes about in The Bellows quite a bit, including this piece which discusses agglomeration benefits, "The Internet at Work."

Population density aids agglomeration benefits--it's what Jane Jacobs wrote about in Death and Life in terms of the value of density in supporting a broad range of offerings from retail to public services.

It's why New York City can support a plethora of sidewalk newsstands, corner grocery stores with a wide array of products, and stores open til the wee hours, or restaurants open all night.

You can build fancy vending booths, or work to get kiosks in places (something that even Arlington is working on, see "Arlington Thinks Small for New Business Spaces: County Wants Kiosks To Enliven Urban Areas," from the Post) but if you don't have adequate population, either residential or daytime population during the workweek, you won't be able to support viable offerings. Instead the offerings need to be limited to particular places, times and days of the week. Otherwise they will fail, just like the newsstands and florist booths that had been constructed on Pennsylvania Ave. NW.

See "Yesterday's News," from the New York Times about newsstands. The article includes a slideshow of various newsstands around the city.