In the physical world, shared space is something we take for granted. When you play a card game or a board game with someone, you communicate not only through words, but by indirect interactions in this shared space.
Modern forms of communication allow us to interact with each more conveniently than ever, but do they let us interact effectively? The phone lets us speak to people far away, but we are restricted to audio only. There is no shared space there, so communication is necessarily restrained.
The internet also enables convenient long-distance communication, with the additional advantage that this communication can be intricately networked and widely shared. In addition, it is flexible in terms of the sort of media or communication it can carry.
However, despite its huge potential, we most often constrain ourselves to simple forms of communication. E-mail and instant messaging, for example, restrict us to text, with emoticons struggling to provide some shadow of "real" communication.
Some specialized shared spaces can be found; if you go to the right site you can have a chess space, a poker space, an MMORPG space to share with others. Unlike real spaces, however, these are needlessly constrained, allowing only the limited forms of interaction required for the space's purpose.
What we lack are general-purpose spaces, spaces which can be put to any of a number of uses. When we play a game in real life, there is no computer around to automatically enfore rules we may or may not agree with, and there needn't be online either. Let the users, or players, make of it what they will.