If you're not familiar with what a SWITCH does, first read this page.
Swiches can be divided into two broad categories: DUMB and SMART
DUMB SWITCH - this is much like an appliance which has very limited configuration options. It's strictly a "layer 2" switch. No management page, no vlans, no port controls.
SMART SWITCH - these switches have configurable options usually accessed either via a console cable or web browser. They vary greatly in the amount of capabilities and configurability they can have. In sophisticated cases, some smart witches can even act like routers.
POE SWITCH - this can be a dumb or smart switch which has the ability to provider "Power over Ethernet" (POE). This is necessary when a device connected to the network doesn't have a power supply and therefore needs to get power from the network connection. Examples are. VoIP phones, WiFi access points, IP cameras.