Think you can keep your rendezvous to Montreal a secret between you and your sweetie? Not anymore. Personal data -- such as where you travel, how much you make or even what kind of car you drive -- is no longer considered your private business.
In today's big-data age, marketers routinely mine your personal information for insights into who you are and how you behave. Behind the scenes, data brokers quietly collect and sell some of your most sensitive personal details -- without your knowledge or consent.
As the amount of information up for grabs continues to increase, companies are testing new ways to track your movements on the Web and outside your home to learn even more about who you are and what products you can be persuaded to buy.
"It's increasingly easy to monitor people 24/7," says Justin Brookman, director of the Center for Democracy and Technology's Project on Consumer Privacy.
At the same time, "companies are getting better and better at tying it all together," he says. Rather than analyze a handful of data points -- such as where you live or what you like to buy at one particular store -- today's companies have access to a range of information from different sources and use it to construct an impressively detailed portrait of who you are and how you spend your time.
Marketers -- often aided by data brokers -- are secretive about the total amount of information they amass. But over the past few years, pressure from Congress and the Federal Trade Commission forced some companies to reveal the types of consumer profiling data they collect.
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Here's a rundown of what marketers may know about your personal and public life:
1. They know how much you're worth.
Your boss isn't the only one who has a rough idea of how much money you make. Data brokers routinely collect information about your estimated income and what kind of job you have. They also mine information about how much your home is worth and whether you recently filed for bankruptcy or have a lien against your house.
In addition, "some of the data brokers will try to categorize you into types of people," says Paul Stephens, director of privacy and advocacy at Privacy Rights Clearinghouse. For example, according to publicly available documents online, they might tag you and your spouse as "new money," "young and thrifty," "retirement ready," "prosperous parents," "social insecurity" or "jumbo mortgagees."
2. They know what kind of car you drive.
Data brokers also collect detailed information about the car you own. For example, thanks to public records, data brokers know whether you drive a decade-old Honda Civic or a brand-new Lexus ES.
3. They know your hobbies and if you're good with money.
For years, marketers have been scrutinizing your purchases in order to gain insight into the things you do for fun. "They have a list of what your hobbies are based on your purchasing history," says Stephens, and can target you with advertisements for that hobby.
Some marketers go beyond simple ad-matching and gauge what kind of shopper you are -- how likely you are to pay a certain price for a particular item. "If a company can get a picture of you and your purchasing habits, they may figure out how sensitive you are to pricing," he says. "For example, people who purchase Apple products tend to be perceived as less price-sensitive than people who purchase Windows products."
4. They know about your health worries.
Data brokers may also collect information about your other "health interests," according to information disclosed to Congress. As a result, marketers may be able to infer whether you have arthritis or diabetes, are approaching old age or are trying to cure an ailment through homeopathic remedies or other over-the-counter drugs.
In addition, some data brokers sell information about the medications you currently use. Pharmacies may legally sell your prescription information to third parties, as long as your name isn't tied to the data. According to information advertised by the Texas-based company DataMasters, marketers also have access to any information you "voluntarily" self-report through consumer surveys, sweepstakes prizes, warranty card registrations, certain types of telephone and rebate coupons and registrations at relevant trade shows.
5. They know what you did last summer.
Based on your purchasing history and other information, data brokers also may know what you do with your time off work, according to information disclosed by Acxiom. For example, if you recently took a cruise or vacationed in Canada, data brokers have access to that information and will add it to their databases.
In addition, data brokers regularly collect information about any public licenses you hold. So if you frequently spend your time hunting, fishing or boating, data brokers can figure that out, too, based on the licenses filed with your state.
6. They know about your love life.
Depending on what kind of information you've disclosed online, third parties may also have access to even more intimate details about your life. For example, according to a 2012 Wall Street Journal investigation, the dating site OKCupid, which is owned by Match.com, has previously shared information with third parties about users' self-reported sexual orientation, as well as their drug use and smoking habits.
7. They know how much time you spend on Facebook.
"A lot of people don't realize that their website searches are being recorded," says Ryan Dochuk, co-founder of TunnelBear, a VPN provider that helps people surf the Web using a masked IP address. However, digital marketers have been looking at what you do online for years. According to Dochuk, marketers track the pages you visit, the time you spend on each site and whether you bought anything. They may also look at which search terms you use and follow you around as you browse different sites.
In addition, a number of data brokers record your social media activity, according to information disclosed in a 2012 congressional inquiry. For example, some look at which social media sites you use and whether you're a light or heavy user. Others round up whatever public tweets, Facebook likes, comments or reviews you make available online.
8. They know where you hang out.
"People don't really think about the fact that their cellphones are a personal tracking device," says the Center for Democracy and Technology's Justin Brookman. If you've ever downloaded an app that uses location-based services, the app can track your movements and follow you around town.
Companies may also be able to track you using the Wi-Fi that's enabled on your device, says TunnelBear's Dochuk. Some retailers, for example, will follow your signal around a store and check out where in the store you like to hang out.
9. They know your race, ethnicity and religious affiliation.
Data brokers also collect a variety of demographic information about who you are and what kind of environment you live in. For example, data brokers may sell information about how many kids you have, whether you're married or single and how many people live in your house. In addition, marketers may be able to buy information about your family's race and ethnicity, religious affiliation -- even which language is spoken at home.
10. They know what you like to read, listen to and watch.
Magazine publishers regularly trade your subscription information so other publishers can target you with offers for similar publications.
Music streaming services, meanwhile, may share "anonymized" information about your listening history (or information you make public), according to the privacy policies of major services, such as Spotify and Pandora. In addition, video streaming services, such as Hulu, now have the legal ability to share what you watch with third parties, as long as they ask for your permission first.
11. They know if you just got married or had a baby.
Sophisticated retailers keep close track of major events in your life so they can target you with offers timed to those events, say experts. "They're looking at what would be referred to as 'life event triggers,' " says Privacy Rights Clearing House's Stephens. Examples include buying a house, getting married or moving to a new home.
In order to meet marketers' demand, data brokers routinely collect information hinting at your life's most recent upheavals -- such as the change-of-address form you filed with the post office or the marriage license you applied for at your city clerk's office.
In addition, some marketers and data brokers may look at alternative clues about what kind of life stage you're in. For example, according to the New York Times' Charles Duhigg, major retailers often use sophisticated algorithms based on your purchasing patterns to determine whether you're about to add a newborn to your home.
12. They know which political party you support.
You may feel uncomfortable talking about politics with your friends or co-workers. However, marketers and data brokers may also be able to guess your political leanings, based on publicly available information, such as your voting records and campaign contributions. "If you happen to have contributed to multiple candidates they can draw an even stronger inference," says Stephens.
What you can do if you don't want to be followed
Not much, say experts. "There is very little privacy law in this country," says Brookman. Online companies must provide privacy policies on their websites, which may tell you more about what they're doing with your data. However, marketers, data brokers and retailers aren't regulated the way banks, insurers, medical providers and other institutions are, say experts, so there's little else they need to do.
That's particularly true for brick-and-mortar retailers which, unlike online companies, don't have to disclose whether they sell your information to a third party. That means a retailer can sell your purchase or contact information to another party -- and data brokers can resell that information without your knowledge.
"Unfortunately it's really, really difficult to avoid the information collection because unless you live on an island in the middle of the ocean, you're constantly going to be engaging in activities that at least to some extent are going to be sold to others," says Stephens.
The good news is there are steps you can take to limit your exposure, say experts. For example, if a retailer asks you for your ZIP code when you're paying for an item, don't give it to them, says Stephens (unless you're paying for gas at a pump). "The reason they want that ZIP code is because they want to figure out precisely who you are," he says.
Be careful about sharing your email address as well, says Stephens, since that information can also be used to connect you with other data.
Most data brokers will also allow you to opt out of their data collection programs. However, you'll have to research each one individually and follow the directions on their websites.
In addition, if you're tired of targeted ads online, look for a little blue triangle turned on its side next to any ad, says Genie Barton, director of the Online Behavioral Advertising Program at the Better Business Bureau. If "you click on that icon, it will take you immediately to a place where you're told about what interest-based ads are and link to a place where you can opt out."