1. Social Media
 Social media platforms give marketers access to information on their consumers’ interests, purchases, and demographic traits. This type of marketing is known as customer relationship management (CRM). Marketers use CRM tools to keep tabs on consumers' online activity and tailor their advertising strategies accordingly. As social media grows in popularity market researchers have begun collecting consumer-related data from websites and mobile devices as well as traditional offline channels.


 2. Emails
 Email marketing allows businesses to create and send emails to customers to promote products and services. According to the Direct Marketing Association, email marketing generates $10 billion annually. Email marketing is highly targeted; companies can segment their targets based on demographics, behavior, and interests. Businesses can even target specific geographic locations or people who work at certain organizations. Consumers receive millions of commercial messages daily through email and research shows that the number of spam and unwanted mail emails continues to rise. To avoid being labeled a spammer, marketers should keep their messages relevant, original, and professional.


 3. Credit Card Information
 Credit card information is valuable to merchants because they can track consumer spending habits. If a buyer goes over his credit limit, a merchant can notify him before he spends any additional money. Additionally, retailers can determine what items shoppers want to purchase. By knowing their preferences, merchants can increase sales by tailoring product offerings to meet customers' needs. When purchasing goods, consumers provide their billing information. Companies collect this information to facilitate future transactions between buyers and sellers.


 4. IP Addresses
 IP addresses identify computers on the internet. Companies gather IP addresses to help route traffic efficiently, monitor network performance, and protect against security breaches. Private home networks often share the same local IP address space. Customers may be asked for their IP address when setting up a new modem, router, or computer. In some cases, ISPs sell IP addresses to advertisers or resell them directly to web servers. These transfers take place without the consumer's consent. Advertisers can then use IP addresses to track online shopping habits.


 5. Deleted Text Messages
 Deleted text messages are commonly referred to as “blanks.” The Federal Communications Commission says blank texts cost carriers 30 cents per message. Most wireless providers offer free blanks if consumers buy extra minutes or text messages. Mobile device users regularly delete these blanks to save storage space or to clear out old messages. Researchers estimate that Americans send about 500 million text messages daily.


 6. GPS Data
 GPS data helps people find places and navigate streets using maps and satellite imagery. A location database company called Datalogix sells consumer GPS data to law enforcement agencies and corporations. The company maintains a database containing the real-time location of vehicles and individuals across the United States. Consumer GPS data is collected via smartphones, cellular tracking devices, and automobile systems (infrared, Bluetooth). Many devices transmit user location automatically to social networking sites and other applications.


 7. RFID Tags
 Radio frequency identification tags or transponders are tiny chips embedded under labels in items to track merchandise inventory. Retailers use transponders to control access to stores, prevent theft, improve supply chain efficiency, and reduce shrinkage losses. In addition to tracking physical assets, transponders can be linked to databases to store information on a product, its price, date purchased, and where the item was sold. Transponder manufacturers claim that their technology does not violate privacy rights because data transmissions occur only after permission has been granted. However, some critics say the technology lacks adequate safeguards and could potentially lead to identity theft.