MSN Explorer is a web browser, eveloped by Microsoft, that integrates MSN and Windows Live features such as Windows Live Hotmail and Windows Live Messenger with a web browser. To make use of these services requires a Windows Live ID (formerly known as a Microsoft Passport or .NET Passport). Version 6 of MSN Explorer is built into Windows XP. Version 7 was released at the same time on Windows XP. MSN 8 and 9 were released in 2002 and 2004 respectively.