From Rachel Davies:

In the last few years, the agile software development movement has created a paradigm shift in how we work to understand system requirements. Agile teams shape software systems using a collaborative process, with executable software at its heart and documents marginalised to a peripheral role. This creates a fundamental shift away from tools for managing requirements artefacts. Instead, we need tools that support collaboration and the gradual distillation of business rules into automated test suites.