Selling millions in software with a single letter
This single page letter was sent out to eight CTOs of leading banks across South and East Africa. The letter convinced six to attend the product demonstration for anti money laundering software systems. Two of the six attendees signed up on the day for the software license - a deal worth $1.1M (USD).
The envelope presented a very sensitive question, ensuring the letter would only be opened by the CTO himself.
The letter was a lipogram which stumped the recipients, thus compelling them to attend the event.