26. The system of claim 22 , wherein the context information displayed with the first document includes a pointer to a location of an instance of one of the sets of matching elements in the second document.
22. A computer system, comprising: a processor; a memory; a program module, wherein the program module is stored in the memory and configured to be executed by the processor, the program module comprising: instructions for repeatedly identifying sets of matching elements and associated locations of the matching elements in the first document and the second document until there are no further matches, instructions for determining instances of unchanged elements between the first and second documents, instructions for determining instances of moved elements between the first and second documents, wherein the determination of the instances of moved elements is based on a relative location difference of the identified matching elements in the first and second documents, and instructions for assigning identifiers to instances of the set of matching elements, wherein the identifiers identify a relationship for the corresponding instances of the set of matching elements, and wherein assigning the identifiers comprises: assigning an identifier indicating unchanged elements to instances of the set of matching elements in the second document when the associated location of the set of matching elements is the same for both the first document and the second document, and assigning an identifier indicating moved elements to instances of the set of matching elements when the associated location of the set of matching elements is different for both the first document and the second document, and displaying the first document and the second document with context information based on those portions of the second document that are associated with the identifier indicating unchanged elements, the identifier indicating moved elements, or both.