There are three main types of pins.
Drawing pins have a pin that pushes into the corkboard and a rounded, almost flat head. Commonly used for long term notices or public notice boards.
This type of pin has a plastic part that sticks out, allowing easy removal of the pin after it is placed. This allows quick removing of notices or repositioning.
The map pin allows you to see where the pin is stuck fairly accurately. The pin has a small rounded head which is kept away from the map by a few millimeters, allowing you to see exactly where the pin has been placed.