It makes sense that websites try to be attractive, but a commonly used tool—the “personalize” function, which remembers the things you’ve clicked and preferentially moves similar items to the top—is also serving as a filter that keeps Web users from seeing all that’s available. While that may seem convenient—who wants to wade through things that don’t interest us?—it’s also very dangerous; what you don’t know can in fact hurt you. In The Filter Bubble: What the Internet Is Hiding From You, Eli Pariser explores how personalizers work (at least, as much as anyone knows) and outlines how they’re working to further segregate online communities rather than to bring them closer together. If never being exposed to a differing viewpoint is your goal, Google will be fine. If, however, you’d like to be truly well-informed, you might want to try some of his suggestions about varying our sources of cyber-info.