There is no doubt that the Internet has made a profound effect on everyone's lives. It has also begun to liberate education from the confines of traditional time and space. The first incarnation of what everyone think of as K-12 virtual school appears to have been launched in the summer of 1995, with the CyberSchool Project in Eugene, Oregon. Since then, virtual schools have grown so quickly that a it is hard to determine how many there are. Some people confuse virtual schools with home schooling, or with charter schools. The truth is that virtual schooling is more like a hybrid of public, charter, and home schooling, with ample dashes of tutoring and independent study thrown in, all turbocharged by Internet technology. In this article, the authors identify the six defining dimensions of "virtual schooling": comprehensiveness (whether the activity is complete or supplemental); reach (whether spanning a district or the entire globe or something in between); type (whether public, private, charter, contract, magnet, or even home school); location (in school, at home, somewhere else,or a combination); delivery (synchronous or asynchronous); and control (run by a school district, university, state, other provider, or combination). The authors also discuss the examples of several more-established virtual schools to provide readers with an idea of what these establishments "look" like, and cover several reasons why individuals choose virtual schools over more traditional educational establishments.