Self-mailers are most simply defined as a piece of mail without an envelope. Self-mailers can be sent flat on a thick paper stock or they can be folded into two or more panels. Postcards, bi-folds, tri-folds, and booklets that are sealed before entering the mail stream are examples of a self-contained mailing format. They can be sealed using glue lines, wafer seals, or glue spots along the edge.
Self-mailers are readily identifiable as marketing mail, so they are prone to receiving lower response rates.
For this reason, some businesses use them for mailing to people with whom they already have a relationship—loyal customers who will open them simply because of their relationship with the brand. Others use them for campaigns in which people want promotional mail. Examples include promotions around clearance sales, new store openings with discounts, and free samples. We see them heavily used around college recruiting, as well.
In the end, choosing the correct format depends on your target audience and the goals of the campaign. Test some different options to see what works best for your business!
Aradius Group is a commercial printing company that specializes in marketing strategy, specifically with direct mail, based out of Omaha, NE.