I work for Google (though not in Silly Valley) and see no obvious sign of age discrimination here. I was 46 when hired.

(approximate) ages on my team at Google: 26, 32 (me), 35, ~55, ~60, ~70.

Approximate ages on my team: A bunch of 20 year olds, a slightly lesser bunch of 30 year olds, and an even smaller bunch of 40 year olds. So far, I think none of us have reached 50. That's due to lack of candidates, same as with women. (And yes, there's outreach for that area too)

If you know experienced engineers looking for a job, please send them our way.

Why is this surprising? CS is a relatively young major compared to other engineering degrees. Also, I would bet that a large majority of CS degrees have been handed out in the last 20 years. Probably more skewed towards the last 10.

I don't have the statistics, but my impression from the Googlers I interact with is that they are generally older than the average developer.