This ruling from the senior level GMs at CCP games for EvE Online makes for some interesting gameplay.
What the ruling basically means is that anything you do, so long as a number of well-coordinated people can do it just as well, is permitted.
Keystroke replication (the act of having a program or piece of hardware send any keystroke you put in be sent to multiple other programs at once) is permitted, since you need to still press the keys.
Automated keystroking (having a program perform ALL the keystrokes for you) is not permitted. This is what we refer to as macroing.
I might consider using keystroke replication if I were actually in need of that sort of synchronization, right now I don't.