Web browsers are applications used for retrieving, presenting and traversing information on the World Wide Web. Hyperlinks present on web pages allow the user to visit other pages; this process is called web browsing. Browsers are normally used to browse the Web, but they can also be used to access private servers of local file systems.
The first web browser, called WorldWideWeb, was created by Sir Tim Berners-Lee in 1990 when he was working at CERN. The world's first popular web browser was Mosaic released by NCSA; soon after that, the Mosaic team Leader Marc Andreessen founded his own company, Netscape, and released in 1994 Netscape Navigator, which became immensely popular (90% of all web usage), to the point of people saying "Netscape" when referring to the Web (similar to how now most people say "Google" when referring to performing a web search). This soon changed with the release of Internet Explorer by Microsoft, which was an important step in the Browser Wars.1
Other important browsers and projects that started in the 1990s are Opera and and the Mozilla Project.