The Poster Stamp Collectors Club has now absorbed the website “Alphabetilately”. If you go to www.alphabetilately.org you will see the introductory page with an added line at the very top.
“Proudly Provided to you by the Poster Stamp Collectors Club”
The start is an introductory page in Alphabetilately, click on the blinking stamp image just below the word Introduction and get to the table of contents. You’ll see a grid with variety of subjects to browse. Some of these sections concern postage stamps and general philately, but many are Cinderellas and Poster Stamps. There is a lot to look at, as this website was created 25 years ago and has gradually been growing ever since. William M. [Bill] Senkus, the creator and owner of this site, has been at it long enough that he wished to retire from maintaining the site, and he has graciously given it over to us so that it could stay open. As part of our own internet hosting, it costs us very little to keep it open for the foreseeable future, so it will remain open to all guests–members or not.
At the moment, not every link is working, as there are some compatibility issues to be worked out, which will gradually be corrected.

If you are curious about this set of stamps, you can read a bit about it in alphabetilately. Go to the contents page and click on P is for Poster Stamp Bulletin. Then go to Volume 1 Number 4 in the index (issued in 1936).
This link will get you there to page 1 of the issue directly, where you can see that the stamps above are from the Jimmie Allen radio show, sponsored by Richfield Oil Co. (and later Skelly Oil).