Gen Y/ Millenials see the world differently than someone from the class of '62. Back in post WWII America, recent grads would seek out employment at blue chip companies like IBM, GM or 3M. The bigger the company, the better. Back then big companies were well established and nearly guaranteed lifetime employment. It was an unspoken rule that if you did your job diligently from 9 to 5, you could count on a long, stable career. Major corporate downsizing and rightsizing in the late 20th century broke this trust. It was a violation of what Reed Hoffman calls the "Employer-Employee Compact."
Suddenly a big company doesn't look immediately attractive anymore to a Millenial graduate. You get big bureaucracy and big headaches with little guarantee of job security. Now more than ever it's important for the largest companies to tout their talent brands and corporate culture as a selling point to Gen Y.