3. The information processing apparatus as claimed in claim 1 , wherein the at least one annotation object comprises a plurality of annotation objects, wherein each of the plurality of annotation objects added on the page through the annotation operation control unit is associated with group identifying information, and wherein the electronic document data holding unit stores the group identifying information associated with each of the plurality of annotation objects in page data corresponding to the group identifying information.
3. The information processing apparatus as claimed in claim 1 , wherein the at least one annotation object comprises a plurality of annotation objects, wherein each of the plurality of annotation objects added on the page through the annotation operation control unit is associated with group identifying information, and wherein the electronic document data holding unit stores the group identifying information associated with each of the plurality of annotation objects in page data corresponding to the group identifying information. 5. The information processing apparatus as claimed in claim 3 , wherein the annotation operation control unit, in response to the operation input receiving unit receiving an input of the user to copy to another portion of the page at least one of the plurality of annotation objects having the group identifying information at the portion of the page, associates the group identifying information and the magnification to the copied at least one of the plurality of annotation objects.