1. Netscape Navigator (1994)

Netscape was the reason people started spending hours a day on the Internet, leading to the boom (and bust) of many a Web site. The advent of the browser also led to the U.S. Department of Justice's antitrust suit against Microsoft, after the company embedded Internet Explorer into Windows. And Netscape's August 9, 1995, IPO is universally considered to be the official start of the dot-com era.