We present the Really Easy Displays framework (RED), a web-based platform to facilitate spontaneous interaction between devices and applications. RED provides a single abstraction for content and interaction between display types, data streams and interaction modalities, and allows developers to create multi-display applications by enabling the sharing of web document object models (DOMs) across displays. We present lessons learned from using RED in our own research, hands-on workshops with developers and interviews with long-term developers over the course of a year. We provide initial evidence that the use of web-technologies in a framework like RED can mitigate some barriers encountered in by multi-display interaction scenarios, and we propose future work to improve RED.