An RPG designed specifically for online play?
Here's a question to ponder: We're all familiar with taking a conventional set of PnP RPG rules like HMG and playing online via an IM or perhaps via a more sophisticated tool like the one provided by RPGTonight. In such cases, though, the rules were designed to be played with pen, paper, and dice; they neither take advantage of the computer's potential, nor do they compensate for its shortcomings.
So, imagine you're starting from scratch (or if you prefer, with HMG) and designing a set of rules that will be incorporated into software for "online PnP gaming". What would they be like?