Externalities

In economics, the effects that the acts of consumers or producers have on each other. Externalities range from pollution and technological (see technology ) inventions to the change in the range of options available to consumers and are differentiated from internalities because current knowledge prevents the former from being included into the formal equations of an analysis. Externalities may also be regarded as the unanticipated side effects of calculated courses of action. (Krippendorff )