You are not the only one that is confused. My answer to the question about greeting cards was not exactly correct. When doing some research on recycling cards, I discovered that there is a better answer. First of all, glossy or slicks are described as looking like photographs. Using that description, a few greeting cards are glossy and they go in with magazines. However, most greeting cards, thank you notes, announcements, and postcards are matte and they go in with office paper. Color is a not a factor, unless it is glossy. What difference does it make whether a card is put in with paper or magazines? The difference is that office paper is worth several times what magazines are worth at a paper mill. The same is true with the newspaper advertisements. Glossy looking ads go in with magazines, all other ads stay in with the newspaper. Just as office paper is worth more than magazines, so are newspapers worth more than magazines.