The first widely used web browser was NCSA Mosaic. The Mosaic programming team then created the first commercial web browser called Netscape Navigator, later renamed Communicator, then renamed back to just Netscape. The Netscape browser led in user share until Microsoft Internet Explorer took the lead in 1999 due to its distribution advantage. A free open source software version of Netscape was then developed called Mozilla, which was the internal name for the old Netscape browser, and released in 2002. Mozilla has since gained in market share, particularly on non-Windows platforms, largely due to its open source foundation, and in 2004 was released in the quickly popular FireFox version.