The document discusses the Software Development Life Cycle (SDLC), including its objectives, common phases and models. The key models described are waterfall, prototyping, spiral, RAD and agile. Waterfall is the classical sequential model but is inflexible. Prototyping and spiral address changing requirements through iterative cycles. RAD focuses on rapid development through reuse, workshops and early user testing. Agile methods emphasize speed, reduced formal processes and adaptability. The conclusion recommends RAD for mashup projects due to its support for iterative requirements changes and modular development.