Howmuch.net
The folks at HowMuch.net have broken down what one person using the services of these companies is worth to that company.
They calculated this by taking the number of active users and dividing that number by the company's market cap - the number of shares multiplied by the price of each share.
Here is what they found:
You can check the data for yourself here >>
Disclosure: Jeff Bezos is an investor in Business Insider through hispersonal investment company Bezos Expeditions.