I started collecting pinup postcards a few weeks ago, mainly out of curiosity. Seems unlikely these cards ever traveled by mail, unless they were inside a brown paper envelope. Most of them have satin or linen finishes which make the photos slightly blurry. Perhaps they were novelty items, sold in adult bookstores or at newstands. It's kind of interesting and quaint to think back to a time (1950s - 1960s) when people bought and traded sexy postcards the way we buy and share sexy files today.