Virtual worlds are designed for specific age groups. However, in most cases these sites are open to users of all ages. The age for which the site was designed is usually mentioned in the parental guide. Parents and carers should be aware that when children below the stipulated age access a site, they could encounter content that is potentially harmful or meet with older players who could pose a threat to their wellbeing. The available features and content on any site are intended only for users of or above the designed age. Children can claim to be any age and there currently are no well established, widespread and foolproof tools to verify age.