This post has some useful advice on how and when to implement an NPS survey. As someone who is implementing it for the first time at my company it was helpful to learn that LinkedIn sees NPS as a lagging indicator and that they don't expect to see a meaningful change right after product launches. It takes time for users to internalize the change and thus change their "promote" opinion.
I was a bit surprised that they only survey NPS once a quarter. I'd expect this to be an ongoing weekly survey, especially since LinkedIn has the traffic to get significance quickly from a small % of their visitors.
https://twitter.com/andrewchen/status/696777766377623552