Both icon association and attachment association are used to associate QubiMap objects with third-party application interfaces. For icon association, placemark description is used as input and output items of third-party applications, while for attachment association, attachments are used only as input items. Placemark description can be at most 30KB in size and must be in text format. Attachments, however, have no limits in size and format; they can be text or large video files. Icon association supports third-party application output (that is, writing content back into placemark description), while no output is generated for attachment association. Furthermore, description is part of the placemark information, while attachments are the associated items of placemarks. The placemark information only includes the attachment number and not the content itself. Therefore, when you sync placemark data or share placemark data with your friends, the placemark description is already included, while the attachments must be processed separately.