Here's a couple of retail history sites I found:
Retailers from Woolworth to Wal-Mart
The guy who did this website describes it best:
This site is just a small overview of how retail changed over the past years with pictures, facts, local stories [New England] and more. You can learn about store chains that you never or barely knew, you can share your comments, pics and story with us, we have many links, shopping centers overview, towns descriptions, retail news update...
Groceteria.com is a site about supermarket history and architecture, roughly covering the period from the 1920s to the 1970s. It is NOT a site about current supermarket issues and locations, except in historical perspective, and it is not connected with nor owned by any supermarket chain, past or present.
The webmaster grew up in Greensboro and he devotes a large portion of his site to grocery store history in that city. I knew many of the places he mentioned. On a side note, I think this is the same guy who did the article on Carolina Circle Mall, but there is not a connection made on his site.