Platform virtualization allows you to create virtual machines that behave like physical computers, enabling you to install multiple operating systems and programs on a single machine at once. It uses hypervisor software to emulate hardware and allocate resources to guest systems, while the actual hardware resources belong to the host system. Popular virtualization platforms include Xen, Microsoft Virtual PC, Qemu, VirtualBox, and VMWare, and virtualization provides benefits like safe testing of new software and running multiple systems simultaneously on a single server.