The principle of cooperation influences our everyday lives. This conflict between individual and collective rationality can be modelled through the use of social dilemmas such as the prisoner's dilemma. Reflecting the reality that real world autonomous agents are not chosen at random to interact, we acknowledge the role some structuring mechanisms can play in increasing cooperation. This paper examines one simple structuring technique which has been shown to increase cooperation among agents. Tagging mechanisms structure a population into subgroups and as a result reflect many aspects which are relevant to the domains of kin selection and trust. We will outline some simulations involving a simple tagging system and outline the main factors which are vital to increasing cooperation.