Tabs

[trevorw]

Ctrl - T opens new tabs in FF

[greenlandy]

www.mozilla.org/support/firefox/keyboard

[Ballistic Banana]

or right click, open tab will have the same effect

[ThePassenger]

Or middle click (i.e. click the scroll wheel on your mouse).

[greenlandy]

ThePassenger said:

Or middle click (i.e. click the scroll wheel on your mouse).

Not on my f**ing mouse

[Plotloss]

Or mouse gesture 'up'