I haven't any idea, Tal, but sincere thanks for the link to that site. A treasure for a history and nostalgia buff!
I heartily recommend
Shorpy Historic Picture Archive | Old Photos & Fine Art Prints for any and all who are interested in old photos - most not really posed. There are photos from the 1840's to the 1970's, with great sub-categories of many cities and other topics. Very similar to the photographic content of your site.
Thanks again. Nice gesture.
