17. The data display method according to claim 15 , wherein said relational metadata represents a relational strength with a degree of relevancy based on the number of pieces of relational metadata, and a value obtained by counting the relational metadata having the item data IDs equal to each other is defined as the degree of relevancy.
15. A data display method making use of a user terminal and a data display server connected to a network to display prescribed data in response to a request from said user terminal, said method comprising the steps of: storing posting data including (i) a posting message, a posting ID identifying the posting message, and an item data ID, said posting data having been posted through said user terminal and (ii) responsive posting data including a responsive posting message, a posting ID identifying the responsive posting message, and an item data ID; storing reference data specified by the item data ID contained in said posting data and item data specified by the item data ID contained in said responsive posting data; when posting data having the item data ID specifying item data regarding contents of the posting message attached thereto is posted by said user terminal and the responsive posting data to which the item data ID is attached is posted in response thereto, extracting the item data ID one by one from the posting data and the responsive posting data according to a relationship between said posting data and said responsive posting data to generate relational metadata with said extracted item data IDs contained therein; and juxtaposing and displaying, on a display of said user terminal, said item data and relational data associated with said item data by said relational metadata, in response to item data browsing request from the user; wherein said item data is one or more pieces of information selected from a group comprising the item data ID, an item data name, an alias item data name, a model number, a manufacturer name, a category, a descriptive text, an image URL, a price, and a release date, wherein said relational data is displayed in an order suited to a type of relationship to said item data, and said relational metadata associates the item data specified by the extracted item data IDs.