Surveying employment-related newspaper advertisements over several centuries, we identify four eras (neither workers nor firms posted ads, mostly workers posted ads, mostly firms posted ads, and both parties regularly posted ads). These eras can be understood in the context of the equilibrium of a matching model that incorporates strategic interactions by both sides of the labor market. Potential explanations for transitions across eras include increasing literacy rates, expansion of social insurance programs, growth in the labor force and firm size, reduction in mobility costs and search frictions, and the internet.