The scent was added to the color printing process and is activated by warmth or friction to release the fragrance.
In 1973 the nation of Bhutan issued scented rose stamps. In 1999 Brazil issued four smoke-scented stamps to highlight the dangers of forest fires (now there's a big idea!). And in 2001 Switzerland issued chocolate-scented stamps.
Maybe they are onto something. Could USPS create a buzz with their own scented stamps? What should they smell like? Click here to add your suggestion!
(If you scratch your computer monitor, a special scent will be released. Try it!)