User:Nick Gardner /Sandbox

Citizendium is non-rivalous and is constitutionally non-excludable, and is thus a public good (collectively financed by its supporters). Although roads and bridges are usually government-financed and are no-rivalous (except when congested), they are not public goods because barriers can be used to exclude those unwilling to pay tolls.

There are products and services, other than club goods, that cannot be exclusively categorised as either public goods or or private goods.