If you've ever wanted to search or navigate without disrupting the page you're currently reading, you've probably opened a new tab to do so. This means either clicking the "new tab" button at the end of the tabstrip, or using the "new tab" menu item or keyboard shortcut (ctrl-t).
A little-known shortcut can help you do this even faster.
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If you type something in to the omnibox and hold down the Alt key while you press enter, the resulting page will open as a new tab at the end of your tabstrip, leaving your previous page untouched.