Just a pointer to two interesting applications/services that seem to make a web 2.0 savvy use of decentralized structures:

Fundable is a site for raising money for a variety of use cases (both charitable or philanthropic and commercial) like:

Split the cost of something big
Pool money for birthday gifts, real estate, parties, shared items, etc.
Buy a product in bulk to save money
Raise money for a personal project from friends
Collect dues ahead of time and eliminate excuses
Avoid getting stuck covering costs when someone in the group doesn’t pay.
Confirm demand before selling
Secure a minimum number of sales before going into production.

and Kiva addresses a similar concept on a global scale:

By choosing a business on our website and then lending money online to that enterprise, you can “sponsor a business” and help the world’s working poor make great strides towards economic independence. Throughout the course of the loan (usually 6-12 months), you can receive monthly email updates that let you know about the progress being made by the small business you’ve sponsored. These updates include reports on loan repayment progress, photos of new capital equipment, narratives on business growth and standard of living improvements, and more. As loans are repaid, you will get your original loan money back.

(via Boing Boing)