Usually based on corn syrup, these syrups are meant to taste something like maple syrup and to be put on (North American style) pancakes.
Though it is fashionable to knock Pancake Syrup as being a "cheap imitation of maple syrup", these syrups are nummy in their own right, are great on pancakes, and make a great addition to baked beans, etc.
Many people in fact prefer Pancake Syrup to maple syrup, as maple syrup is very expensive, and they are tired of the maple syrup taste, anyway.