[joshamania]

I think it's more about the commoditization of employees than anything else. Big companies seem to have trended to thinking of and treating their employees as commodities. A piece of furniture that can be swapped in and out at will. I don't know that it's willful discrimination against older workers so much as willful disregard as to whether or not they're getting the best employees.

A company like Facebook probably doesn't really care that they get the absolute best employee for 90% of their open positions. They go with the group that's going to get them the largest number of acceptable hits so they don't need to work as hard to filter out candidates that they're not interested in.

This is all speculation on my part, I have nothing to cite in this regard. I think it's fairly obvious that if Facebook filters out over-40's for these 90% of jobs right up front they will have less work to do gleaning the wheat from the chaff.

For the remaining 10% of high-productivity/high-value workers they probably wouldn't use such pre-screening and do more targeted recruiting. Again, this is all a guess on my part, but it makes sense. Not saying it should be legal, but I can understand why they do it.