I have a silver bullet answer:
Don't build terrible, dehumanizing, sprawl-encouraging, traffic-encouraging headquarters out in suburbia.
This isn't my idea - it's what every progressive minded thinker that spends even two minutes thinking about urban/traffic/sprawl ideas arrives at.
If google, facebook, et. al, were in the city, the network and wealth effects would be staggering. How many boats would be lifted by that rising tide ?