短语词组短语network externality 网络外部性;连带外部效应;网络Adoption externality 使用外部性;外部性externality principle 外部性原则;外部性内在化原则Positional Externality 外部性security externality 安全外部性Informational Externality 息外部性Reciprocal externality 双向外部性 返回 externality