Store loyalty cards can earn shoppers discounts at stores like pharmacies and grocery chains but companies track that information and can sell it to advertisers.
According to ProPublica, data companies are collecting information about nearly every American. They'll sell that information about whether consumers are pregnant, how much money they earn and diet plans. Shoppers may be giving this information without even knowing it.
Where does the information come from? When you fill out an application for a card, shoppers give stores information like name, telephone number and address. There's even a spot for the number of children in a household.
It's all a part of the consumer data industry. When consumers shop and scan a loyalty card, the purchase is recorded.
However, some people don't care what information is being tracked.
"Because I'm using my ex-girlfriend's card number. So they can have all they want," said Jack Butler with a laugh as he walked into Albertsons.
But those who use their real name, phone number and address, don't like that date being sold to marketing companies.
"They say that it doesn't get out so do we take them at their word or do we do some kind of investigation," said Victor Harmon, Santa Barbara resident.
The fact that companies track and sell shoppers' information, won't stop some people from continuing to swipe those cards.
"Oh yeah, because they save you discounts. I'm a starving college kid. I make minimum wage!" said Stephen Warnick as he held up his new rewards card.
Although much of the information can be bought and sold without any input from the consumer, there is some data companies cannot buy and sells. It includes medical records and credit reports.