This update contains new features including:

• Reading List: Easily add webpages and links to your Reading List to browse when you have time.
• New Process Architecture: Safari has been re-engineered for improved stability and responsiveness.
• Resume: In the General pane of Safari preferences, you can now choose to launch Safari with the windows from your last browsing session.
• Better Privacy: A new Privacy pane in Safari preferences makes it easy to remove data that websites can leave on your system.

Other improvements include:

• Private AutoFill: Safari lets you fill out forms quickly while keeping your personal information private.
• Find Option: When you use Find, you can choose whether you want to search for text that contains or starts with the text that you type in the search field.
• Better Graphics Performance: Safari 5.1 hardware accelerates animations and CSS3 effects for faster performance.
• Advanced Web Technologies: Safari introduces support for full-screen webpages, media caching with the HTML5 application cache, MathML, Web Open Font Format, CSS3 Auto-hyphenation, CSS3 Vertical Text, CSS3 Text Emphasis, Window.onError, and Formatted XML files.
• New Extension APIs: Developers can take advantage of new Safari Extension support for popovers, menus, new event classes, and interaction with Reader.