This document provides an overview and history of Web 2.0 and social media theory. It discusses how science fiction envisioned modern digital technologies, defines key aspects of Web 2.0 like user-generated content and collaboration. The document also covers social media adoption cycles, different social platforms' approaches and positioning, and evolving business models in this space. Theories discussed include Gartner's Hype Cycle, Metcalfe's Law, and the long tail. The document emphasizes that foundational strategies and theories continue to drive digital marketing success despite constant interface changes.