Yes, and almost everyone who uses e-mail or surfs the Web is an open source software user. Most e-mail passes through an open source server during its travels across the Internet. Most Web servers rely on open source software. Google is based on open source. As OSI points out, the running gears of the Internet, including the mail transports, Web and FTP servers, are virtually all open source-based.
Open source software is not warez, which is software distributed without permission of the copyright holders or a proper license.
