Mass Installer allows to install a bunch of extensions with one single click.
If you work at many different places or clean your profile frequently, you’ll be hunting and installing extensions more often than necessary. Mass Installer tries to simplify this task:
* Collect the links to all of your favorite extensions (i.e. to the XPIs) in a text file (one URL per line).
* Put this file online or onto some portable media (wherever Firefox can find it).
http://forums.mozillazine.org/viewtopic.php?t=225555
