Tabbed browsing is a feature new to Internet Explorer but common in other browsers such as Firefox and Opera.
This allows you to open multiple web pages in the same IE window that you can switch between by clicking on their respective tabs at the top of the screen.
To try this, instead of left-clicking a web page link, right-click it and select Open in New Tab, or alternatively press your middle mouse button.
A new page will be opened but your current page will still be on-screen. You can access the new page by clicking on the new tab which appears at the top above the page, and has the page's title. To close the tab, click the X button on the tab or right-click and Close.
You can keep one tab open and close all others by right-clicking it and selecting Close Other Tabs.
To the left of the tabs is an icon called Quick Tabs which appears when you have more than one tab open. Click this to see at a glance all the pages you have open.
If you try to close IE 7 when you have multiple tabs open you will be asked if you are sure you want to close all the pages you have open.