There is a nice article in the Engineering News-Record issue on June 12, 2004. It lists AutoCAD by Autodesk as number two in the list of the ten technologies to change the construction industry in the past 20 years.
10 Electronic Technologies That Changed Construction (source enr.construction.com)
Computer Aided Design - CAD Pioneers Gave Desktop PCs A Full Range of Electronic Drafting
"AutoCAD was created to bring CAD capabilities to the newly introduced desktop IBM PC and allow "serious computer-aided design" to be done on desktop machines, rather than very expensive, dedicated workstations."
For those into historical AutoCAD information, have a look at my AutoCAD History site.