• Telecommunications: The benefits of having a phone or fax machine are greater the larger the number of people with whom one can communicate. Large telephone networks also facilitate other phone applications such as burglar alarm systems and mail-order operations.
• Applications Software: The greater the number of users of a given software package, the greater will be the benefits to user s in terms of file sharing. For this reason, Microsoft Office has come to dominate the office software business. Microsoft also benefits from network externalities with their Windows operating systems because the large number of Windows installations makes it profitable for other to write applications software only for that system.
• The Internet: Network externalities in the Internet are similar to those in telecommunications. The ability of the Internet to carry any soft of digital file enables a much winder range of interactions than is possible with traditional phone networks, however, Especially problematic has been the ability of the Internet to foster piracy of intellectual property such as music or motion pictures.