Abstract: Open quantum systems fundamentally differ from closed systems in that they allow for the creation and destruction of information. This unique property has led to discovering of various information-theoretic phase transitions, sparking significant interest and research in the field. As a motivating example, I will show that our capacity to prepare long-range entangled state using measurement and feedback can undergo "transition" under decoherence. Then, I will introduce strong-to-weak spontaneous symmetry breaking (SSB) as a unifying framework for understanding these information-theoretic transitions. With this framework, we explore how it generalizes the concept of thermalization and applies to several key phenomena, including fault-tolerance thresholds of topological codes and approximate codes, as well as the emergence of hydrodynamics. If time permits, I will also discuss how charge-sharpening or purification transitions can be incorporated into this framework.