Learning who knows something or where we can find information, rather than remembering the information itself, is a way to expand our mental reach, and the Web has proven better at that than any resource in human history. When we are online, we are essentially linked to a vast hive mind, known in psychology as a transactive memory system, which allows us to access the collective knowledge of anyone and everyone. Some worry that our bargain to become a super-connected, super-knowledgeable society will leave us as individual fools who are helpless without a mobile device, but as usual, Luddites are likely to be left behind.