In my experience talking to FB devs of varying report at conferences, they are often highly motivated and may thus quickly gain a deep understanding of the tech

In my experience talking to FB devs of varying report at conferences, they are often highly motivated and may thus quickly gain a deep understanding of the technology they get to work on, but their overall knowledge tends to be fairly shallow. Most skills are likely transferrable but a kid joining Facebook fresh from college to move on to another job three years later is still a rookie due to their lack of experience.