Microsoft Internet Explorer 6 (commonly abbreviate to IE6), is a graphical web browser developed by Microsoft and included as part of the Microsoft Windows XP and Windows Server 2003 lines of operating systems. It was the most widely used web browser during its tenure (surpassing Internet Explorer 5.x), attaining a peak of about 95% usage share during 2002 and 2003 when it began steadily declining until 2007 when it rapidly lost market share to Windows Internet Explorer 7.