Abstract: A method for managing contents shared by a Social Network Service (SNS), executed by a cloud server which is associated with an account of the SNS. It is detected whether a first content has been newly uploaded to the SNS or whether a metadata related to the first content previously uploaded to the SNS has been newly added. A second content corresponding to the first content is searched. The cloud storage is updated by linking context information related to the first content to the second content corresponding to the first content. The cloud server interworks with an account of the SNS of each user's individual to link context information of content shared on the SNS with the content stored in the personal cloud storage, thereby enabling easier update of the cloud storage. A user may easily search for desired contents using the context information.

Abstract: In a synchronization system including a local terminal, latest metadata of a file in a local storage and latest metadata of a file in the server storage are managed in a first tree database, which is a virtual database in a local terminal, and each of the local terminals is allowed to upload or download a changed file on the basis of the metadata in the first tree database so that a conflict that may occur due to multiple users simultaneously changing files can be minimized.