Shared memory is a method used in computing where multiple processes can access the same memory space. This allows them to communicate and share data efficiently without needing to copy information between different memory locations. It is commonly used in systems where speed and performance are critical, such as in operating systems and parallel computing. In shared memory systems, processes can read from and write to the same memory area, which helps reduce the overhead associated with inter-process communication. However, it also requires careful management to avoid conflicts, as simultaneous access can lead to data inconsistency. Techniques like mutexes and semaphores are often employed to synchronize access.