Editing Barter (section)

==Recent developments==
In Spain (particularly the [[Catalonia]] region) there is a growing number of exchange markets.<ref>{{Cite video
  | title = Homenatge A Catalunya II
  | url   = http://www.homenatgeacatalunyaii.org/en
  | medium = Motion Picture
  | publisher = IN3, Universita Oberta de Catalunya, Creative Commons Licence.
  | location = Spain, Catalonia
  | date = 2010
  | access-date = 15 January 2011
  | ref = homenatgeacatalunyaii
  | quote = A documentary, a research, a story of stories about the construction of a sustainable, solidarity economics and decentralized weaving nets that overcome the individualization and the hierarchical division of the work, 2011.
}}</ref> These barter markets or swap meets work without money. Participants bring things they do not need and exchange them for the unwanted goods of another participant. Swapping among three parties often helps satisfy tastes when trying to get around the rule that money is not allowed.<ref>[http://faircompanies.com/videos/view/barcelonas-barter-markets-an-antidote-to-overconsumption/ Barcelona's barter markets] (from faircompanies.com. Accessed 29 June 2009.)</ref>

Other examples are El Cambalache in San Cristobal de las Casas, Chiapas, Mexico<ref>Erin Araujo (2018/1-2) Moneyless economics and non-hierarchical exchange values in Chiapas, Mexico. Journal des anthropologues  (n° 152-153), pages 147-170</ref> and post-Soviet societies.<ref>Paul Seabright (2000) The vanishing rouble : barter networks and non-monetary transactions in post-Soviet societies. Cambridge [etc.] : Cambridge University Press.</ref>

The recent blockchain technologies are making it possible to implement decentralized and autonomous barter exchanges that can be used by crowds on a massive scale. BarterMachine<ref>Ozturan, C. (2020). [https://ledger.pitt.edu/ojs/ledger/article/view/148 "Barter Machine: An Autonomous, Distributed Barter Exchange on the Ethereum Blockchain"], Ledger, 5.</ref><ref>[https://www.bartermachine.org BarterMachine] (from www.bartermachine.org Accessed 5 September 2021.)</ref> is an Ethereum smart contract  based system that allows direct exchange of multiple types and quantities of tokens with others.  It also provides a solution miner that allows users to compute direct bartering solutions in their browsers.  Bartering solutions can be submitted to BarterMachine which will perform collective transfer of tokens among the blockchain addresses that belong to the users.  If there are excess tokens left after the requirements of the users are satisfied, the leftover tokens will be given as reward to the solution miner.