Simple mod to allow the player fast placement of multiple signs, by holding down a key (Default Left-Alt), which doesn't open the sign Gui every time you place a sign.
Futhermore you can edit existing signs by sneaking and right clicking a sign, which opens the sign Gui and let's you change the text.
Install:
Drag the jar to your minecraft mods folder, normally found in '<username>\%AppData%\Roaming\.minecraft'