A phone tree is a network of persons organized in such a way that they can quickly and easily disseminate information amongst each other. These trees are especially common among parents, who often want to be able to communicate quickly about canceled events and other issues, and they are also used by activists and a variety of other groups as well. Setting up a solid phone tree takes time, but many people feel that it is well worth the effort, since the list can be used again and again. Basically, a phone tree is organized by a single person, to eliminate confusion. The person organizing the tree collects information about all of the individuals who should be included in the list. Phone tree is as a like a phone pyramid. One person at the top of the pyramid calls two people, who each call two more people, and so on, until every person in the list has been called. This allows people to distribute information quickly, without placing the burden of work on one person. There are a number of advantages to setting up this type of organization, not least of which is the ability to distribute information quickly in a crisis.