From Business Week Online, a nice profile of ETS founder Henry Chauncey:
In the early 1930s, Harvard University's graduating classes were made up of young men and (a few) women who had spent their teen years reveling in the heady 1920s. It seemed to one young Harvard assistant dean, Henry Chauncey, that these sons and daughters of the elite were simply expecting that they would rightfully inherit top positions in business and society, as if the Great Depression couldn't touch the ruling class.
Chauncey, a Harvard grad himself, was distressed to watch as class after left the august institution, and failed, in his view, to meet the titanic civic challenges of the times. Together with then-Harvard president James Bryant Conant, Chauncey initiated an experiment to bring Harvard a new type of student, based not on the connections they or their parents had, but solely on what the students knew and their potential for further learning.
Many people would like to forget (if indeed they ever knew) the proud principles upon which ETS was based. Yes, there are still inequalities in our educational system, and students with more wealth and health and good fortune still tend to do better. But it's a far cry from the days where, if you were very smart but from a poor family in Nowhere, Kansas, you were completely out of luck, and tests like these have a lot to do with that.