As editor of the CCN magazine, I use the ChipGuide for historic information for some articles. Postcards are useful to me when it comes to finding photos, logos, and other facts. I know some people send in postcard images without the back of the card. There can be historical info on the back, the year printed, or the postal cancelation, comments, info about the photograph, etc. This information is helpful when researching. Thank you for reading and your assistance.