3M Shelved Post-it Glue for Five Years Before Anyone Wanted It

Spencer Silver was trying to make a stronger glue. In 1968, working on aerospace adhesives at 3M's research labs, he produced microspheres that stuck to surfaces but peeled off cleanly, leaving no residue. That was a failure by the brief. 3M filed it under "solution without a problem," and Silver spent the next five years giving internal seminars trying to convince anyone that a glue you could un-stick was useful for something.

Art Fry sat through one of those seminars. In 1974, he was singing in his church choir and his paper bookmarks kept slipping out of the hymnal. He remembered Silver's adhesive, found some, and brushed it onto a strip of paper. The bookmark held. More importantly, it came off the page without tearing it.

The canary yellow was an accident too. The prototype paper came from scrap stock in the lab next door, which happened to be using yellow that week. Nobody picked the color. It was just what was on the cart.

3M test-launched the product in 1977 as Press'n Peel in four cities. It flopped. Shoppers picked it up, didn't understand it, and put it back. So in 1978 the company tried something more direct: hand them out. The Boise Blitz dropped free pads on offices and homes across one Idaho city. Ninety percent of the people who tried one said they'd buy more. The national launch followed in 1980.

3M now makes more than 50 billion Post-it Notes a year. Silver's glue was the right answer to a question nobody had thought to ask for a decade.