The ability to generate blocks is a show of computational strength, which is just what the Bitcoin network needs to help verify all the transactions. But it is also a show of community spirit because by agreeing to enter the contest for the next block, they show themselves to be willing to respect the interests of the community rather than manipulate the block chain for self-interested purposes. This is just the sort of thing that should be expected to hold a community together. @Satoshi Nakamoto Institute

The Proof-of-Work Concept | Satoshi Nakamoto Institute

Proof-of-work should not be seen as a mysterious or wasteful system, but as something functional, natural, and potentially of value for the design ...