1. A computer-implemented method for use with an annotation system: wherein the annotation system includes first data for annotating a manifestation of a first instance of a first XML document; wherein the first data comprises: a first XML document identifier for the first XML document; and first annotation data representing a first association between: (a) a first manifestation of first annotation content in connection with the manifestation of the first instance of the first XML document and (b) a manifestation of a first instance of a first target in the manifestation of the first instance of a first XML document; wherein at least one of the first annotation content and the first target is not text; wherein the first data is uniquely identified by a first Unique Annotation Link Identifier (UALI); wherein the first instance of the first XML document is served by a document system; wherein the annotation system is functionally independent of the document system, wherein the annotation system and the document system share no state by contract; wherein the document system is configured to respond to a request containing the first XML document identifier with a manifestation of a second instance of the first XML document; the method comprising: (A) receiving a first request containing the first UALI; (B) in response to the first request containing the first UALI, issuing a second request to the document system, wherein the second request contains the first XML document identifier; and (C) in response to the first request containing the first UALI, manifesting the first annotation data in connection with the manifestation of the second instance of the first XML document.