The document discusses how standalone SaaS applications are evolving into composite applications that combine multiple services. There are three main advantages to this approach: it allows applications to add functionality by integrating new services instead of code, helps integrate applications across the entire enterprise, and opens up new sales channels for SaaS vendors. Composite applications achieve this by utilizing web services from different vendors to share data and functions. This represents a shift from standalone departmental SaaS applications to more flexible enterprise-level solutions.