Wired networking offers no hassle, hard wired connection between computers and devices such as routers to allow file sharing or access to the internet.
Most routers now are wireless but offer wired ports in the back. The wifi transmission can also be turned off so nobody can hijack your connection. . Routers allow for internet to be broadcast and shared between a numbers of computers simultaneously as well as allowing a network to be set up between computers.
Switches are a great solution for splitting one signal into many for applications such as internal networking or using in conjunction with a router to share the internet with even more computers.
Modems are becoming more obsolete due to the introduction of broadband. They are used for dial up connections which come straight from the telephone line rather than a separate connection such as broadband.
Homeplugs are a new technology allowing for the earth electrical cable from the mains power supply to become a makeshift Ethernet cable. This allows for a hard wired connection over a whole house without the need for hiding messy cables.
Network cards are used to plug a network cable into. This allows computers to share files or connect to the internet via a router.