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Initiatives by topic
The word Decidim translated from Catalan means we decide, and it's the name of Barcelona's digital infrastructure for participatory democracy. One part functional database and one part political statement, organizers say Decidim is key to a broad digital transformation that is taking place in Barcelona — its institutions, markets, and economy. Organized by the Barcelona City Council, Barcelona's citizens participate in a new digital commons, and its organizers hope that technology can improve democratic participation and foster good government. The open-source platform allows the public to participate directly in government as they would a form of social media, and they have had early success. The city council hosted several organizing events to decide on a strategic plan, and nearly 40,000 people and 1,500 organizations contributed 10,000 suggestions.
Decidim was born when a young protest movement in Spain swept into power, according to Xabier Barandiaran, a project leader, who compares the fledgling political party to the Occupy movement in the U.S. Its leadership's first goal was to create a platform for open strategic planning for the city. "People were in the streets and saying let's participate in democracy, let's write a strategic plan," Barandiaran said.
What developed was an open-source software that embodied the group's transformation plan, a digital common where citizens can have a say in government — the code is available on Github. "We decided how we would decide," he said. 
wikipedia:List of markets in Barcelona: The city of Barcelona has a great many neighborhood markets that provide meat, fish, and produce on a daily basis, and are still vital to the urban life of the city.
Wikipedia: Barcelona, Parks
Towards sustainable economies
The city of Barcelona has launched an experiment testing several potential reforms of its anti-poverty programs, including new social programs as well as unconditional cash payments. 
News and comment
City of Barcelona Kicks Out Microsoft in Favor of Linux and Open Source, Jan 12 
Barcelona's Decidim Offers Open-Source Platform for Participatory Democracy Projects, Sep 5 
Barcelona acts to address climate change, Jul 20 
How Barcelona is reducing daily car journeys, Jul 3 
Building the Networked City From the Ground Up With Citizens, Jun 27 
Barcelona has always been a centre of radicalism. Now the City’s €1bn spending power is being used to build a more democratic economy, Apr 10 
El ayuntamiento crea Barcelona Energia para autoabastecerse de electricidad, Mar 30 
From ‘smart cities’ to ‘smart citizens’: when technology meets activism, Mar 29 
How Progressive Cities Can Reshape the World — And Democracy, Mar 10 
Eight lessons from Barcelona en Comú on how to Take Back Control, Mar 8 
Barcelona Plans Europe's Largest Car Ban Yet, Mar 7 
Barcelona Crowdsourced its Sharing Economy Policies. Can Other Cities Do the Same? Jan 18 
Barcelona will offer free public transport to those who get rid of their polluting car. Dec 13 
Barcelona's Brave Struggle to Advance the Commons, Nov 22 
Barcelona, primera ciudad “Veg-Friendly” del mundo, May 30 
Superblocks to the rescue: Barcelona’s plan to give streets back to residents, May 17 
Food For Thought: Why Barcelona’s Markets Are “Super” Places, May 30