We argue that the coming of the Internet era has raised issues that traditional object-oriented software engineering methodologies seem not ready to address. In this paper, we first discuss the intrinsic limitations of the object abstraction in the engineering of complex software systems, and compare it to the agent abstraction. Then, we show how an agent-oriented methodology should take into account inter-agent aspects such as the modelling of agent societies and of the agent space, by providing engineers with specific, ad hoc abstractions and tools. 

To this purpose, we introduce the SODA agent-oriented methodology for the analysis and design of Internet-based systems. SODA supplies the abstractions and procedures for engineering agent societies as well as the agent environment, including social infrastructures. The main idea in SODA is to exploit coordination models, languages, and infrastructures to address social issues. In particular, SODA shows how to choose a coordination model, how to exploit it to design social laws, how to embed them into a coordination medium, and how to build a suitable social infrastructure based on coordination services.