I remember hearing in a podcast that openbazaar.org tried this approach but because of unreliable clients parts of the network would be completely unaccessible. They then went with a partially decentralized solution with a few main nodes always supporting the system. I'm not sure what has changed in the design since that podcast episode though.
I'm not sure which podcast that was. Currently content is served by others that have viewed that content, but new content gets pushed to a few configurable nodes to store that content before anybody has viewed it. This allows vendors to make changes and shutdown the software immediately instead of needing to wait until somebody has viewed their change.
