Ageism?

Don't bother applying for a job at Facebook if you got your college degree before 1980.

The dropdown for "Graduation Date" on their job application doesn't go back that far.

Addendum:

In an industry survey, a majority of technology companies candidly said they would not hire anyone over 40.

New York Times, article in "This Week" section on June 22, 2008, titled "For a Good Retirement, Find Work. Good Luck."