Features of Internet Explorer 8
InPrivate Browsing
This is a safety issue in IE8 that allows you to browse the web wherever you want and the browser will not save your browsing history, temporary Internet files, form data, cookies, and usernames and passwords.
It does allow you to access your bank details in internet cafes etc but always remember that features like this are not perfect so still always be alert when accessing private information in public places.
To browse with InPrivate Browsing you must open a new tab and select Browse with InPrivate.

Web Slices
This is a cool feature that allows you to keep track of your favorite website without constantly opening up a browser, instead you can get new updates just from your favorites bar.
On a webpage that is using Web Slice you will see a green icon at the top-right, click this and subscribe.
Accelerators
Accelerators in Internet Explorer 8 help you quickly perform your everyday browsing tasks without navigating to other websites to get things done.
Just highlight any text on a webpage and click the blue icon underneath it, you will notice a list of accelerators come up. Here you can use that text easier than opening up a new page etc.
You can even search up an address easy with the map feature.

Instant Search
There are a bunch of new search features (including visual search) that you can see on IE8, the improved search helps you search and find things easier and faster.
It even incorporates websites that you have visited before in the search results.
You can play with the options by clicking the manage search providers icon in your search drop down menu.
SmartScreen Filter
This is a new security feature that prompts the user whenever a potential threat (malware, spyware etc) is evedent on a webpage. Quite similar to the UAC feature on Vista, your PC will warn you whenever a danger is nearby, but like UAC some people may get annoyed quickly by the constant warnings.
You can turn the filter on or off by going to the safety dropdown and scrolling down to SmartScreen Filter.

