11. A system for storing multiple versions of a structured document, the system comprising: a processor-based command handler component executed on a computer and configured to receive a first and a next version of a structured document comprising a plurality of objects hierarchically related to one another, wherein the first version is received temporally before the next version of the structured document and wherein the next version of the structured document includes a modification to a first object of the first version of the structured document; and a processor-based versioned node (vNode) manager component executed on a computer and configured to: generate a plurality of vNodes representing the plurality of objects of the first version of the structured document when the first version is received, wherein each of the plurality of vNodes includes versioning information associated with the first version of the structured document; store the plurality of vNodes in a data store, wherein the plurality of vNodes collectively represent the first version of the structured document; identify a sharable object of the first version of the structured document when the next version of the structured document is received, wherein the sharable object is identified based on a hierarchical relationship between the sharable object and an ancestor of the modified first object; and update a vNode representing the identified sharable object to include versioning information associated with the next version of the structured document, wherein the updated vNode is shared between the first version and the next version of the structured document by including versioning information associated with the first version and the next version of the structured document.
12. The system of claim 11 wherein versioning information associated with a structured document comprises at least one of a version identifier identifying a version of the structured document, a check-in date of the structured document, and a creator name of the structured document.