Ripple

Ripple is a friend-to-friend network based approach to banking / currencies / credit.


 * Homepage: http://ripple.sourceforge.net/
 * FAQ: http://ripple.sourceforge.net/faq.html

It basically allows you to specify some amount of credit that you grant your friends, and when someone wants to buy some goods or service from someone else, the ripple system finds a path between the buyer and seller, transferring the credit in the form of debt between friends. The transaction only works if a path can be found that allows the specified amount of credit to be transfered.

The Ripple model could be used to implement banking and currencies in game worlds. The nodes in a Ripple network can be either private persons, or organizations. The concept is relatively simple, and a superset of how banks are implemented nowdays (they can be seen as essentially a small ripple network, where private person nodes and normal business nodes only have connections to bank nodes, while bank nodes are linked together in a small network). So if the Ripple system is implemented, it could be used to model either current banking systems, or more futuristic peer-to-peer systems.

Apart from being an interesting social experiment and very web 2.0-ish, it also sounds like it could be a relatively robust way of implementing currency and an economic system. An interesting detail is that NPC:s could participate in the system on equal basis as other characters.

If it turns out to work well, an interesting extension would be to connect it with emerging real-world Ripple networks in the future, allowing an easy way to convert between real world currency and debt inside the game (also allowing NPC:s to indirectly participate in real-world economy, as far as players are ready to trust them to pay back their debts, and they trust players to pay back theirs).

Some issues could arise with players who leave a game and leave behind a lot of debts - but as you can only accumulate the amount of debt that people are willing to give you, it should be relatively self-correcting. People tend to not trust random newbies, and some in-game friends are also real-life friends.