Retailers may assume you're pregnant or trying to get pregnant by what you buy, law enforcement may profile you as a potential criminal, and health insurance companies may decide if you're a good risk to insure.
"There is more information ever in the world and we can do new things with it that we never could before," Kenneth Cukier said.
Cukier is author of "Big Data: A Revolution That Will Transform How We Live, Work, and Think." He says when we use a loyalty card to buy something, information about our purchase history is built up. When we do an online search, that information is stored. And when we surf the Internet, data is compiled about our interests and activities. That information is used to determine the likelihood of what we might do in the future.
But, Cukier warns, profiles even based on the best data are still only predictions.
"We could rightly say that in fact there's no guarantee that we would act in the way that we might even if the algorithm says that we have a 98 percent likelihood of say shoplifting, or being an unwed teen mother or not replaying a loan, or not surviving a surgery and therefore being denied an operation," he said.
That has some consumers concerned.
"When they start divulging information about how I live, where I live, what I buy and they make the information public then that is an invasion of my privacy," Pleasanton resident Richard said.
Richard is so guarded about his privacy he asked 7 On Your Side not us use his full name. He's especially concerned about online data brokers like Spokeo that use public records to gather information about us, then publish it online.
"All that information together provides a much more in-depth profile of you than just a simple Google search of your name," he said.
Anyone can access Spokeo and get that information for free and more detailed information if they're willing to pay for it.
"Data brokers know your home address, they'll know your age, they know who your family members are, your parents, your siblings, your children, maybe your aunts and uncles," American Civil Liberties Union spokesperson Nicole Ozer said.
But Spokeo tell 7 On Your Side the service it provides is not as sinister as some describe. It declined an on camera interview, but by email said: "We have built our business around the notion of transparency and democratizing data; making the same data that is used by large corporations for multiple business purposes available to individuals to help them connect with others."
"You know we've seen real examples in the past few years about people's credit being ruined by false information in data broker reports," Ozer said. "People have lost mortgages, seniors have been scammed."
But Cukier believes profiling is not necessarily a bad thing if used in positive ways. For instance he sees nothing wrong with sending consumers targeted ads or making social services available to certain demographics.
But he's concerned about impacting individuals in a negative way.
"In the past we never had a situation whereby we could be penalized prior to acting, but in this instance we can because big data is often about predictions," he said.
A bill currently stalled in the state legislature would allow consumers to request from a company any information that has been collected about them. The bill would also force companies to tell consumers how they share that information. It's called the Right to Know Act.
The tech industry is strongly opposed to it. The group Tech America told 7 On Your Side, "We have some very real concerns that several of its provisions are unworkable from a compliance standpoint for tech companies...placing excessive and impractical requirements on tech companies that will inevitably lead to litigation will jeopardize the innovative and responsive nature of our industry that consumer have come to expect."
"It's our personal information and we should have a right to know what's happening to it," Ozer said.
The bill has been pulled from this legislative session and will be brought back next year.