This update contains improvements to usability, compatibility, stability, accessibility and security, including the following:
More accurate Top Hit results in the Address Field
More accurate results in Top Sites
Fixes an issue that could cause content delivered with the Flash 10.1 plug-in to overlap webpage content
More reliable pop-up blocking
Improved stability when typing into search and text input fields on www.netflix.com and www.facebook.com
Improved stability when using JavaScript-intensive extensions
Improved stability when using VoiceOver with Safari
For detailed information on the security content of this update, please visit this site: http://support.apple.com/kb/HT1222