1. Detach a Tab To a New Window
Firefox 3.5 now has it but it was Google Chrome which introduced it. You can easily click and drag a tab outside of the main browser window to a new window.

Here are some of the unique features that are only available in Google Chrome which are not available in other popular browsers like Internet Explorer, Firefox, Apple Safari or Opera.
1 - Task Manager for Websites

Inside Google Chrome, press Shift+Escape and it will open up a ‘task manager’ with a list of all websites currently open [...]