The document discusses Sequoia Capital's TAM/SAM/SOM framework for evaluating startup investment opportunities. It explains that Total Available Market (TAM) is the overall market size, Serviceable Available Market (SAM) is the subset that could use the startup's products/services, and Serviceable Obtainable Market (SOM) is the portion the startup can realistically obtain. For startups, public relations is important to grow awareness and trust through earned media coverage in order to expand the SOM and give marketing efforts a larger audience. As coverage increases, the startup can obtain a larger portion of its SAM. PR also helps startups bridge to new markets as their products evolve beyond the initial SAM