This paper explores the theoretical and empirical literature to examine the use by different social groups of informal sources of information provided by friends, relatives, and acquaintances during job search and its consequences for the job market. It also addresses the role of network structure and size, the resource endowments of contacts, and nature of the links between contacts to explain differences in the effects of job information networks. In doing so, the paper also turns to the sociology literature on job information networks and provides an economic perspective on such sociological concepts as strong versus weak ties, inbreeding, distance from structural holes, etc. The paper distinguishes between models of exogenous job information networks, that is where individuals obtain job-related information through a given social structure, and endogenous job information networks, which are social networks that result from individuals' uncoordinated actions. The paper pays special attention to such issues as physical and social proximity and sharing of information and discusses them in the context of the recent social interactions and neighborhood effects literature. Finally, the paper outlines a model that integrates job information networks, where interactions occur in business cycle frequencies, with the dynamics of human capital formation, which include the joint effects of parental, community and neighborhood human capital, and are set in life cycle frequencies, for the purpose of organizing suggestions for future research and examining earned income inequality.