The chip was fairly successful and years later someone out in the world noticed the funny blinking on their retail USB drive that used it and they figured it out. They wrote a letter to the editor of Byte or Dr. Dobbs or something, wondering what the message "Sis you rock!" meant. Twisted sister fan, maybe?
We saw the letter in the magazine and were chuffed that our easter egg had hatched but... It turns out the designer had typoed the table of ASCII-to-morse values and dot/dash timing he used to build the messaging circuit, so it really was saying "Sis you rock!". And because he also wrote the test it didn't catch the error. Doh!