15. The system of claim 11 wherein the sharable object of the first version of the structured document is a child of an ancestor of the modified first object and is not itself another ancestor of the modified first object, and wherein the ancestor is a parent of the sharable object.
15. The system of claim 11 wherein the sharable object of the first version of the structured document is a child of an ancestor of the modified first object and is not itself another ancestor of the modified first object, and wherein the ancestor is a parent of the sharable object. 18. The system of claim 15 wherein when the modification to the first object comprises one of replacing the first object with a new first object, the vNode manager component is configured to generate a new first vNode corresponding to the new first object, wherein the new first vNode includes versioning information associated with the next version of the structured document, and store the new first vNode in the data store.