12. A method according to claim 8 , wherein the metadata includes a plurality of annotations of the content data, the annotations including a first annotation generated by a first application and a second annotation generated by a second application.
12. A method according to claim 8 , wherein the metadata includes a plurality of annotations of the content data, the annotations including a first annotation generated by a first application and a second annotation generated by a second application. 13. A method according to claim 12 further comprising: managing a first access control list (ACL) which is used to control restriction of access to the object and a second ACL which is used to control restriction of access to the plurality of annotations.