Mosaic has been described as "the killer application of the 1990s" because it was the first program to provide a slick multimedia graphical user interface to the Internet's burgeoning wealth of distributed information services (formerly mostly limited to FTP and Gopher) at a time when access to the Internet was expanding rapidly outside its previous domain of academia and large industrial research institutions.
NCSA Mosaic was originally designed and programmed for the X Window System by Marc Andreessen and Eric Bina at NCSA. Version 1.0 was released in April 1993, followed by two maintenance releases during summer 1993. Version 2.0 was released in December 1993, along with version 1.0 releases for both the Apple Macintosh and Microsoft Windows. An Acorn Archimedes port is underway (May 1994).
Marc Andreessen, who created the NCSA Mosaic research prototype as an undergraduate student at the University of Illinois left to start Mosaic Communications Corporation along with five other former students and staff of the university who were instrumental in NCSA Mosaic's design and development.