From Shadow Work, by Craig Lambert, loc 2884:

Routinely, businesses now ask shadow-working customers to cough up personal information as a way to smooth transactions, or even enable them to buy things at all. To make online purchases, customers open accounts with bookstores, banks, newspapers, utilities, sports teams, apparel vendors, phone service providers, and so on. Everyone wants you to open an account. This means supplying contact and demographic data and then having all transactions tracked, building a personal profile for the vendor. That profile enables vendors to activate “recommendation engines.” Once its algorithms have examined your past purchases, Amazon can recommend books or desk lamps you might like, and Netflix can suggest movies to rent. On my computer, opening Amazon.com brings up thumbnails of books by Bill Bryson, an author whose works I have purchased, and books on pharmaceutical companies, a topic I’ve browsed.