1. A server apparatus that stores a content acquired from a client device in a storage unit, said server apparatus comprising: a content segment acquisition unit configured to sequentially acquire, from the client device, comparison counterpart segments constituting a part of a candidate content, each of the comparison counterpart segments respectively corresponding to one of a plurality of comparison segments constituting a part of one or more already acquired contents stored in the storage unit; a duplication decision unit configured to, while said content segment acquisition unit continues to sequentially acquire the comparison counterpart segments constituting the part of the candidate content, (i) compare, each time said content segment acquisition unit acquires one of the comparison counterpart segments constituting the part of the candidate content, the acquired comparison counterpart segment and the one of the comparison segments corresponding to the acquired comparison counterpart segment, and (ii) determine, based on a result of the comparison, whether a content including the one comparison segment that corresponds to the acquired comparison counterpart segment is present among the already acquired contents; and a content acquisition unit configured to acquire the entire candidate content from the client device and store the acquired candidate content in the storage unit in a case where said duplication decision unit determines that the content including the one comparison segment that corresponds to the acquired comparison counterpart segment is not present among the already acquired contents, wherein said content segment acquisition unit is configured to abort an acquisition of a comparison counterpart segment that is subsequent to a currently acquired comparison counterpart segment of the part of the candidate content, in the case where said duplication decision unit determines that the content including the one comparison segment that corresponds to the acquired comparison counterpart segment is not present among the already acquired contents.