Patent ID: 8615560

Claim:
A document data sharing system including a user apparatus that transmits and receives e-mail and a server apparatus that registers different versions of document data and provides the document data to the user apparatus, wherein an e-mail received by the user apparatus includes at least identification information for uniquely identifying the e-mail, and further includes, when the e-mail is a reply to other e-mail, reply identification information indicating the identification information of the other e-mail, the user apparatus comprises a transmitting unit that, when registering document data attached to a received e-mail in the server apparatus, examines the reply identification information of the e-mail to which the document data has been attached, thereby generating a list of identification information of one or more past e-mails related to the e-mail and transmitting a registration request including the list and the document data to the server apparatus, and the server apparatus comprises a registration unit that determines a version of the document data to be registered indicated by the registration request based on the identification information in the list included in the registration request received from the user apparatus and registers the document data in a corresponding hierarchical position, wherein the server apparatus further comprises a storage unit that stores a table in which e-mail addresses and log-on accounts for the server apparatus have been associated, the registration request further includes an e-mail address list in which e-mail addresses have been set as destinations of the e-mail to which the document data to be registered indicated by the registration request was attached, and the registration unit sets a log-on account accessible to the document data indicated by the registration request based on the e-mail address list included in the registration request and the table.