“An important change for site developers to know is that IE9 will send the short UA string by default. This change improves overall performance, interoperability and compatibility. IE9 will no longer send additions to the UA string made by other software installed on the machine such as .NET and many others.
IE9’s Compatibility View will map to IE7 Standards Mode, and IE9’s UA string when in Compatibility View will be: Mozilla/4.0 (compatible; MSIE 7.0; Windows NT 6.0; Trident/5.0). Test how your site responds to the new IE9 UA string (check and change the UA string through the registry),” explain Microsoft.
Learn about IE security which discuss the latest in day-to-day security and privacy challenges. Pete LePage bring some clarity to browser and IE security: