Internet has penetrated into all the aspects of our life and work. We can study and work by it; we can find a job by it; we can communicate by it; we can entertain by it; we can buy and sell by it. We can do almost everything on the internet, almost anywhere any time. 　　However, while providing services for us, internet is inevitably inevitable invading our privacy to some degree. The services on most website require our registration. If we want enjoy these services, we have to provide much private information, including our name, address, gender, telephone number and sometimes bank account number. Due to the poor administration and weak security, our information might be open, stolen or sold on the internet. Even sometimes the information will be misused by the criminals. 　　Considering the above-mentioned, we must enhance the alertness when using the internet. First, when we need internet service, we should try to log on those big legal websites. Second, if the service requires important private information, you should think twice before you type it in.