1. A computer-implemented method for processing structured data content comprising: determining whether Web content delivered through a network includes a content portion matched with a predetermined matching pattern, and if a content portion is determined to match: processing the Web content to associate related information with the content portion of the Web content, the method further comprising: setting a target subtree having nodes relating to a range including a target content portion as an extracted portion of the matching pattern in the Web content from which the predetermined matching pattern is to be extracted; detecting an occurrence mode of each node of the target subtree by selecting a plurality of past Web contents with respect to the Web content and collating the target subtree relating to the target content portion with a tree relating to each of the past Web contents, wherein the occurrence mode detecting step includes detecting: a first occurrence mode wherein detected nodes occur in both of the target content portion and Web contents collated therewith and contents thereof are mutually identical; and, a second occurrence mode wherein the detected nodes occur in both of the target content portion and the Web contents collated therewith and the contents thereof are mutually different; generating statistical information concerning an occurrence frequency of the occurrence mode of each node in the target subtree based on the plurality of past Web contents; and classifying each node of the target subtree based on the statistical information and a result of detecting the occurrence mode, wherein each node of the target subtree is classified into one of: a stationary node of which occurrence frequency of the first occurrence mode is determined to be equal to or more than a first threshold value by the statistical information, an updated node of which occurrence frequency of the second occurrence mode is determined to be equal to or more than a second threshold value by the statistical information, and additional nodes other than the stationary nodes and the updated nodes, wherein classifying the nodes of the target subtree further includes: detecting whether a node relating to an image is a node relating to a formed-for- spacer image for ensuring a blank region; detecting whether or not the node relating to the image is a node relating to a plurality of bullet images used repeatedly in a designated size; a first classifying step of classifying the node relating to the formed-for-spacer image into the additional nodes; and a second classifying step of allocating a plurality of the nodes relating to the bullet image into a classification among classifications of the stationary nodes, updated nodes and additional nodes even if display contents of the plurality of nodes are mutually different; and, generating the matching pattern for the target content portion based on the classification.