Conventional wisdom holds that trademarks are nothing like other intellectual property. Copyright and patent law are theoretically based in public goods theory and are designed to promote creation and disclosure of original expressions and novel, useful innovations. By contrast, trademarks are private goods and trademark law is designed to promote trade and encourage competition. This article challenges conventional wisdom by demonstrating that trademarks are a type of public good that contributes to the public stock of useful ideas just as patented and copyrighted works do. This economic perspective suggests, again contrary to conventional trademark theory, that competitive markets fail to supply an ...