This document discusses linking data across the web and in cloud computing. It covers the evolution from Web 2.0's use of APIs and web services to access data, to current efforts in Web 3.0 to develop a semantic web that can automatically discern meaning and relationships across data sources using technologies like structured search engines and knowledge engines. The document also outlines cloud computing models like IaaS, PaaS and SaaS and provides examples of how companies like Google provide applications and allow data sharing through these models.