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.
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.