The Water Commons
One of the most valuable functions of the concept of "the commons" is that it reframes the terms in which we think of resources. For example, think of water as a commons, and you begin to realise why it really must be shared, and never owned:
One clear lesson emerges from the struggles of the world’s water warriors — water management remains a leaky endeavor unless it adheres to the principles of the commons — the gifts of society and nature that are shared by all, for generations to come. Effective water management must be based on such water commons principles as community control, democratic participation, ensuring the earth’s right to water, public water delivery and accessibility for all.
This comes from the new site Our Water Commons. There's also a freely downloadable report on water commons principles: “Our Water Commons, Towards a New Freshwater Narrative” by Maude Barlow.
It's both fascinating and thorough; drink it up.