Don't know if this would be considered philatelic (more to do with mail than stamps), but I found this kind of interesting. There was an art and history magazine published out of the USA from the late 50s to the 80s called Horizon. It came out in hard cover four times a year. I pick up old copies (well, there are no new ones

) at my local thrift shop occasionally. I still find the articles interesting.
In one I bought today there was a subscription renewal card, but I thought with a bit of a difference.


What I found interesting is that these are do-it-yourself envelopes. Scored along the fold lines and gummed on the flap. I guess the purpose was to give you something to do and somewhere to put your cheque.
Usually these cards are just annoying (a college teacher of mine used to tape bricks to the postage paid ones and drop them in the mail box), but I thought this one at least showed some thought.