At the Seybold Conference, which took place Octobre 1-4, 1991 in San Jose (California), the Adobe founder John Warnock has presented the concept of PDF for the first time in public. I was fortunate to attend this memorable event in person.
I remember very well when Warnock printed the title page of ComputerWeek on a Mac to a file which was copied on a floppy disk. The file was opened on Windows in an application called Carousel (the code name for Acrobat) and looked exactly the same as on the Mac thanks to the embedded fonts. At that time this was sensational since the exchange of completely designed pages between platforms seamed impossible.