This document discusses different models that provide support for startups, including accelerators, incubators, coworking spaces, and government programs. It provides brief histories and descriptions of incubators, accelerators, and their processes. Notably, it outlines the venture-backed business model of seed accelerators, which provide funding, training, and mentoring to startups over a fixed period in exchange for equity. Examples of notable accelerators include Y Combinator, TechStars, AngelPad, and 500 Startups. The document also discusses business incubators and their focus on providing services to support early-stage companies.