The first ISP, or Internet Service Provider, was a commercial version of ARPANET called Telenet, which began in 1974. The first ISP that is still used as of 2014 is The World, which began in 1989.
An ISP is a company that provides Internet access to subscribers of its service. The Internet was first developed as a network between government research laboratories and the participating department of universities. It wasn't until the late 1980s that it was marketed to the public. After the invention of the World Wide Web in 1992, the remaining restrictions of public usage were removed four years later.