A、By searching the network sites. B、By examining the cookies on user computers. C、By sending emails to the users. D、By consultin

(12)If you’re reading this on the Internet, chances are you’re being followed. More than 200 data collection companies and ad networks use approximately 600 different tracking technologies to gather and sell information on people’s web browsing habits, according to Abine, an online privacy firm that tracks the trackers. The online advertising industry is a $31 billion business fueled largely by behind-the-scenes exchanges of consumers’ personal online shopping and browsing habits.
     (13)Web-based commercial data collectors work by quietly dropping bits of code called cookies on user computers, which allow collectors to track what people read, click or buy. That information, collected by companies such as BlueKai and DoubleClick, is sold in real-time exchanges to ad networks, which then target segments of users with ads fitting their interests. Someone who just searched traveling agency for information on Puerto Rico, for example, would be almost instantly hit with ads featuring hotels and resorts there. Billions of these exchanges occur daily. Search engines and social networking sites such as Google and Facebook also track user data to generate targeted advertising.(14)The result? The new cell phone or spring sandals users willed themselves not to buy show up in ads alongside their morning news.
    Companies in the US spend more than $2 billion annually to tap into consumer data, according to Forrester Research. Data trackers, being present everywhere across the web, are collecting, storing and sharing more information than ever before, says Chris Babel, CEO of online privacy solutions provider TRUSTe.(15)" It’s happening on nearly every site, all the time," he says.
Questions 12 to 15 are based on the passage you have just heard.
12. According to the speaker, what is likely to happen when you visit websites?
13. How do commercial data collectors on the Internet track users’ information?
14. What’s the result of targeted advertising?
15. What does Chris Babel say about data tracking?