Edge connectors are generally used for connecting one PCB to another, the edge connector is plugged in to a socket on another PCB thus making the connection.
Examples of this can be seen on a computer motherboard where you plug a graphics card with a gold edge connector into the socket on the mother board.
Example of an Edge Connector on a PCB
Example of an Edge Connector viewed in a CAM system
The surface finish of edge connectors is usually with what is known as Hard Gold on top of nickel, this allows for the repeated plugging and unplugging of the connector.
To help guide the edge connector into the socket they need to have a bevelled leading edge.
Example of the Bevelling of an Edge Connector