It's hard to imagine life without the Internet. How greatly it has changed our lives in the past 15 years since it was widely used. At the same time, however, the Internet has also caused some traditions to fall away  . E-mail is quicker and cheaper. Getting a handwritten letter from a friend has become a rare   pleasure. Who would like to pay 60 yuan for 12 songs in a plastic case if you can find music in the Internet for free? When almost any fact can be found within seconds through Google and Baidu, personal memory becomes less important. The Web can remember it for us. When was the last time you watched the world out of a window? When was the last time you read a favorite book once again? When was the last time you sat in the cinema with your family? More and more people lose themselves in the Internet. They show less interest and spend less time in the outside world. You've spent the past few years talking with your friends on QQ, or reading about his or her QQ square, so meeting a friend is no longer as important as it once was. Have you ever found yourself doing homework with one eye on a QQ Space window? A growing number of people say the Internet is stopping young people from fixing their attention on anything for a long time. When you surf the Internet, it feels like something you're enjoying and nobody knows it. But when you realize just how many people are watching your every move, it might just make you mad. Many people have realized their personal information can be found easily in the Internet even they don't want to. According to the passage, the Internet has been widely used since  _   ago.
12 years 14 years 15 years 60 years