Memory is a central component in every computer system. Hardware evolution has led to greater capacities and higher speeds, but essential properties of its hardware/software interface have been unchanged for decades: Main memories used to be passive, largely homogeneous, and volatile. These properties are now so firmly anchored in the expectations of software developers that they manifest in their products. However, a wave of innovations is currently shattering these assumptions. In this sense, several new memory technologies are disruptive for the entire software industry. For example, new servers combine “high-bandwidth memory” with classic memory modules and CXL enables even more hybrid architectures (non-homogeneous). The “in-/near-memory” computing approaches abandon the Von Neumann architecture and promise huge performance improvements by allowing CPU-independent processing of data objects in or close to the memory (non-passive). Finally, “persistent memory” is available for servers and embedded systems (non-volatile). Overall, the expectations are high. Computers could have lower energy consumption, more performance, improved reliability, and reduced costs. However, from the (system) software perspective it is largely unclear how to use the novel memory technology efficiently. The DFG priority program 2377 addresses this problem. This overview discusses the state and potential of disruptive memory technologies, the challenges for system and application software, and important research directions.