Requirements engineering (RE) involves human-centric activities that require interaction among different stakeholders. Traditionally, RE has been considered as a centralized, collocated, and phase-specific process. However, in open source software (OSS) development environments, the core RE activities are iterative and dynamic and follow a rather decentralized software engineering paradigm. This crosscutting characteristic of open source RE can be conceptualized using the “Twin Peaks” model that weaves RE together with software architecture. Although many weaving mechanisms have been proposed in recent years, the lack of theoretical underpinning limits a mechanism’s applicability and usefulness in different scenarios. In this research, we hypothesize stakeholders’ social interaction as an ecologically valid weaving mechanism of the “Twin Peaks” in open source RE. In this work, we use the phrase “stakeholders’ social interaction” to indicate interaction among stakeholders regarding the software system that takes place through some communication means, such as posting comments and artifacts over the issue tracking system. We investigate the influence of stakeholders’ social interaction in different RE activities, in particular, requirements identification, creativity in RE, and requirements implementation of OSS systems. This research enables us to gain valuable insights to generate guidelines for enhancing software engineering practice in relevant areas.