In Greenland and under traditional Inuit law, criminals are almost never imprisoned. Fined, yes; if very serious, then exiled - but jail is intolerable to these freedom- loving people. Cyberspace loves equally its own freedom, which is of expression, and its severest penalties would never end someone's capacity to express completely, for such silence would equal not just imprisonment but death. Cyberspace will always prefer to punish by extracting fines, in kind if not in cash.

Prisons, like other penalties, have many purposes. First, to deter crime with the threat of unpleasant consequences for criminals. Second, to realize those unpleasant consequences, in the hope that criminals do not repeat their acts. Third, and this is where jails differ from other punishments, to keep the world safe from those who would be dangerous if let loose.

But to imprison you do need a police force, something quite out of place in the information anarchy of cyberspace. The informal systems of goodwill law - the incidental result of cryptographic technologies underpinning the knowledge economy - don't suit enforcement, and no police means no jail.

Not very obviously, no police does not mean no penalties - fines (and exile) can work quite well in a voluntary legal system. Every participant in the knowledge economy depends on others for survival, and if the others respect an article of goodwill law demonstrably violated by someone, then the violator, the criminal, is vulnerable to any collective penal action taken by them. In this situation, punishment does not necessarily involve the payment of a fine, but could take the form of an exclusion of criminals from economic activity for a certain duration, or a reduction of their earning capacity.

This sounds very complicated, but is not, really, if one remembers that here 'economic' does not have anything to do with money - the meaningless numbers of hard cash - but with knowledge. Knowledge is quite worthless without human interaction, so withholding that has as much of an economic impact in the communication society of cyberspace as does taboo in a rural village. Following this line of reasoning, we find that the net worth (or earning capacity) of an organization or individual is more than just numbers, and includes its social standing, its position amidst all that feverish interaction - in other words, its reputation.

This reputation, attached to every entity on-line, comes from the impressions of all else who interact with it, and in turn affects that interaction. A fall punishes, a rise rewards, both socially and economically. And since reputations are by nature not issued by a single authority but evolve from widely shared opinions, they effectuate a system of continuous, distributed and voluntary justice.

Of course these fines of social standing will work as a practical part of goodwill law only if there is some organization behind them, some method in the interactive madness. There is - reputation systems, which use experimental technology for automating the use of reputations as a filter in communications, promise to make goodwill law work. With them, there should be no need for jails in cyberspace - or jailers.