High Quality Content by WIKIPEDIA articles! Windows Internet Explorer 8 (IE8) is a web browser developed by Microsoft in the Internet Explorer browser series, released on March 19, 2009. It is the successor to Internet Explorer 7, released in 2006, and is the default browser for Windows 7 and Windows Server 2008 R2 operating systems. As of January 2011, estimates of IE8`s global market share ranged from 26 percent to 33 percent.