3M invented a glue that was too weak to hold anything — it became the Post-it Note

In 1968, Dr. Spencer Silver, a scientist at 3M, was trying to develop a super-strong adhesive for the aerospace industry. Instead, he created a 'low-tack, reusable, pressure-sensitive' adhesive that was weaker than anything 3M had ever made. It could hold paper to a surface, but the paper could be lifted off without leaving residue. 3M had no use for it.

Silver spent five years promoting his 'solution without a problem' inside 3M. He gave seminars, demonstrated the adhesive, and tried to find someone who could use it. Nobody could. The project was nearly killed multiple times. 3M's 'bootlegging' policy — which let engineers spend 15% of their time on personal projects — was the only thing keeping it alive.

In 1974, Arthur Fry, a 3M colleague who had attended one of Silver's seminars, was frustrated that his bookmark kept falling out of his hymnbook at church choir practice. He remembered Silver's weak adhesive and applied it to a piece of paper. It stuck, held, and came off cleanly. Fry realised the bookmark was just the beginning — the adhesive could make a whole new category of office product.

3M test-marketed the product as 'Press 'n Peel' in four US cities in 1977. The results were disappointing — nobody bought it. In 1978, 3M tried again with a different approach: the 'Boise Blitz,' giving free samples to offices in Boise, Idaho. Over 90% of recipients said they would buy the product. Post-it Notes launched nationally in 1980 and became one of 3M's most successful products, generating billions in revenue.