Every hour, an active Google user can generate hundreds or thousands of data “events” that Google stores in its computers, said people familiar with its data-gathering process.
These include when people use Google’s array of Web and mobile-device services, which have long collected information about what individuals are privately searching for on the Web. It includes the videos they watch on YouTube, which gets more than one billion visitors a month; phone calls they’ve made using Google Voice and through nearly one billion Google-powered Android smartphones; and messages they send via Android phones or through Gmail, which has more than 425 million users.
If a user signs in to his or her Google account to use Gmail and other services, the information collected grows and is connected to the name associated with the account. Google can log information about the addresses of websites that person visits after doing Google searches.
Even if the person visits sites without first searching for them on Google, the company can collect many of the website addresses people using Google’s Chrome Web browser or if they visit one of millions of sites that have pieces of Google code, such as its “+1” button, installed.
Android-based phones and Google Maps can collect information about people’s location over time. Google also has credit-card information for more than 200 million Android-device owners who have purchased mobile apps, digital books or music, said a person with direct knowledge of the matter.