Meaning – The term Blue Letter refers to the document that was used by IBM to announce a new product release. It was termed as a blue letter, simply because it was printed on a piece of blue paper, and this blue paper contained all the information related to the product like the generalized product description and specifications.
These Blue Letters became the means to make the IBM representatives, the absolute experts at the product that the company is launching. Over time, the content of the blue letters started getting printed on ivory sheets, and the name then changed to ‘Ivory Letters’.
Example of Usage – “The IBM Employee recalled the time when he was given a blue letter and later, an ivory letter as well.”