How does Amazon & Netflix personalization work?

In the recent few years, personalization has taken concrete steps to break out from ‘hype’ and found its calling in marketing deployments across B2B and B2C with equal vigor. Even you, dear reader, inadvertently have been a part of personalization experiments every time you login to Netflix to binge upon that web series you finally found time for. So how do you emulate their personalization recommendation models at scale? This article attempts to decode how two of the biggest internet behemoths, Netflix and Amazon approach personalization from a revenue lens.