I purchased this card for my ADDRESS YOUR MAIL TO STREET AND NUMBER slogan cancel collection. I thought it unusual that the mailer of the card did exactly that as the address clearly includes "91 West St." in Albany NY, but was returned UNCLAIMED.
I decided to see if the street address was still current and thanks to Mr Google I pulled us several real estate listings for the property as well as a location and photo via Google Maps. I downloaded an image of the property which you see here. The structure was built in 1930 and I think was likely a multiple residence building which today has been converted to a single family, 4 bedroom/2 bath home.
I can understand now why the card was unclaimed since an Alpha designation (91-A)was not given. Or perhaps the addressee had simply moved on with no forwarding address.
I am unable to decipher the handwritten annotation in pencil.
A further interesting aspect is that this is an intact card with attached reply, AND, was returned using the prepaid postage of the reply most assuredly because it bore the address of the original mailer and the original card portion did not. Return of such items did not require return postage.
Postally-used cards with attached reply cards are sought by collectors of such as typically they become separated in the process of the transmissions, and one finds either portion separate from the other.
So if one comes across a cover or card with more than ordinary interest, don't simply take it for face value. See what more some simple digging can uncover.