Tim Berners-Lee started his hypertext-based information management at the CERN physics research labs. Text-only pages could be viewed using a simple line-mode browser.

The Mosaic browser was created by Marc Andreessen, a student at the National Center for Supercomputing Applications (NCSA) . Although it was not the first browser to allow graphics to be placed on the page, it was certainly the most popular due to its cross-platform availability. The ability to add images to documents was one of the keys to the Web's rapid rise in popularity. Mosaic also supported sound, video, bookmarks, and forms. All web pages at this time were displayed in black text on a gray background .

Marc Andreessen formed Mosaic Communications Corp. (which later became Netscape Communications) and released the Netscape 0.9 browser. The early browsers were not free (except to students and teachers). To offer a superior experience over such freely available browsers as Mosaic and thereby attract customers, Netscape created its own HTML tags without regard for the traditional standards process. For example, Netscape 1.1 included tags for changing the background color of a web page and formatting text with tables.

Microsoft finally got into the Web game with its first competitive browser release, complete with its own set of tags and features. It was also the first browser to support style sheets, which at the time were an obscure authoring technique.

For years, the web development world watched as Netscape and Microsoft battled it out for browser market dominance. The result was a collection of proprietary HTML tags and incompatible implementations of new technologies, such as JavaScript, Cascading Style Sheets, and Dynamic HTML. On the positive side, the competition between Netscape and Microsoft also led to the rapid advancement of the medium as a whole.

This bold move enabled the thousands of developers to participate in improving Communicator. In the end, they decided to scrap it all and start from scratch. The Mozilla group, made up in part of Netscape employees, guided the development of the open source browser and soon expanded to a complete application platform.

This is significant because it is the first browser to fully support the HTML 4.01 and CSS 1 Recommendations, setting the bar high for other browsers in terms of standards compliance. It is also the first browser to fully support the PNG format with alpha transparency.

This was regarded as Netscape's official loss to Microsoft in the Browser War. Entwined in the operating system of every PC running the Windows operating system, Internet Explorer was a formidable foe. Netscape lost important ground by releasing bloated all-in-one applications and taking several years off to rewrite its browser from scratch for the Netscape 6 release. As of this writing, Netscape is just a blip on the browser usage charts at a mere 1% for all combined versions, compared with approximately 90% for all combined versions of Internet Explorer.

Open source Mozilla code continued development under the newly formed Mozilla Foundation (funded in part by AOL).

Firefox 1.0 caused much fanfare in the development community due to its strong support of web standards and its improved security over Internet Explorer. Firefox is important because it was the first browser to make a significant dent in Microsoft's share of the browser market.