Apple considered this version as a pre-release version of Safari web browser for OS X 10.7 and OS X 10.8; the update is previewed in the picture above.
There is now a sidebar on the left side of the browser, which allows you to view folders easier and quicker.
Continuously read through all the articles and web pages in your Reading List, shared links and comments; this function is only for Mountain Lion.
Shared links will list the links shared from your Twitter followers and enable you to view them on the sidebar:
After clicking on the shared link, a bar appears on the top of the browser, allowing you to easily retweet while browsing:
Non-developers: Safari 6.1 is expected to be available for you later this year.