In November 1992 there were exactly 26 websites in the world. By August 1995 there were more than 10,000. The difference was NCSA Mosaic, a browser begun in December 1992 by Marc Andreessen and Eric Bina at the University of Illinois at Urbana-Champaign, in a lab funded through the High Performance Computing Act of 1991. Mosaic was not the first graphical browser, but it was the first to place images inline with text on the same page, and by September 1993 it ran on Windows and the Macintosh.

This episode treats the software like a biography subject, from birth to early death. Version 2.0 added HTML forms in November 1993, turning the web from a read-only library into a two-way medium and laying the ground for online commerce. Then the commercial potential it revealed destroyed it. Andreessen left to co-found Netscape, Microsoft licensed a Mosaic descendant to build Internet Explorer, and NCSA ended development in January 1997.

• Before Mosaic, the internet meant text tools like Archie, Gopher, and WAIS, and clicking an image link opened it in a separate program.
• Some academic purists hated inline images, seeing them as frivolous decoration that turned a serious research network into a glossy brochure.
• Netscape Navigator displayed text while images were still loading, and its internal code name, Mozilla, stood for Mosaic Killer.
• Mosaic was never open source: NCSA licensed it to Spyglass, which rewrote the browser from scratch and then licensed that code to Microsoft.
• Microsoft paid Spyglass a $2 million fee plus a share of browser revenue, gave Internet Explorer away for free, and later settled the resulting dispute for $8 million.