What kind of information interactions among agents makes possible a functioning of socio-economic systems? What theory do we need to describe the fundamental principles of agents' information interactions? What is the model to simulate functioning of networked economy arisen in Information Society? How we should organize artificial environments where our "intelligent information agents" will interact with each other to help us in our online communications inside numerous human communities? The main purpose of this article is to suggest answers on these questions. Following statements are discussed in the article: Rapid development of Information Society and its Networked Economy attracts attention to the role of information interactions in functioning of social systems. Information interactions are the more fundamental level to describe a functioning of a social and economic system then market or hierarchical interactions. Central element of agents' information interactions is "collective information model" of their environment. There are some limits on information interactions related with parameters of economic system. Institutional structures are able to channel information interactions beyond the limits. Market and hierarchical interactions are just special cases of such channels. Simplest model of economic system functioning with information interactions includes five types of objects (macro-technology, information space, institutional structures, collective information models, and human actors).