His contribution is in response to this past post on Boston's Tremont Theater.
From John Y.: "Here you'll see an early, say, 1905 view of Tremont Street looking north towards Park Street. Just a hair to the right of center, if you look carefully, you'll be able to make out the "Tremont Theater" sign on the front of the marquis, the same as is on the first post card. On the right side of the marquis is "C. S. either Millard or Willard". The dance studio is upstairs and just to the right of that sign is a two-story tall Quaker Oats mural. Other businesses readable are Estley Organs and Weber Pianos. I'm confident that the white stone building at the right edge is the Masonic Temple.
Printed in Belgium for Kosmos Art Co., Boston, this view is dateable mostly because of the lack of electric and/or gas engine vehicles and the existence of the subway.
One of your bloggers, Herb, I think it was, correctly determined that the Astor Theater did occupy the building after our Tremont Theater.
If you or any of your friends would like, and you wouldn't mind being the connection, I'll be glad to share whatever views I have of the City. Just let me know what and whaere and I'll check my stuff."
Here is another from John's collection, dated a year later in 1906: