Do you know where your children are going online? If you don’t, many advertisers do. A Wall Street Journal investigation has discovered that websites catering to children have a much higher incidence of tracking tools than do more generally targeted sites—a 30 percent difference, according to their analysis. Many trackers—though not all—are used to collecting data on where specific users spend their time online, so that advertisers can purchase the information and use it to target consumers. The field is largely unregulated, especially in the case of kids’ sites, which are often run by small mom-and-pop operations. In a survey of the top 50 sites aimed at children, Google was found to have placed the most trackers. The company says only “a small portion” were used to track users’ habits.