A system for determining compatibility between various items is disclosed. A wireless communication device is used to scan a machine-readable tag which includes a plurality of information fields. The information fields include at least identification information of the primary object to which the tag is affixed, list of compatible items, characteristic information of the primary object or other objects, etc. The scanned information from the tag is compared to information in other tags. If the at least some of the information in the tag affixed to the primary object matches the information in one or more other tags, a notification event is triggered to inform the user of the match.