7. A computer-readable storage medium including computer executable instructions for representing non-structured features that span other tags in a ML document, comprising: determining a start feature tag location for a non-structured feature; wherein the non-structured feature spans a range that begins at a location that is after a start tag of an outer element and before an end tag of the outer element; determining an end feature tag location for the non-structured feature; wherein the non-structured feature spans the range that ends at a location that is after the end tag of the outer element; placing a start feature tag at the start feature tag location; wherein the start feature tag does not include other elements and the start feature tag includes a start identifier attribute; and placing an end feature tag at the end feature tag location, wherein the end feature tag does not include other elements and the end feature tag includes an end identifier attribute; and wherein the start feature tag and the end feature tag are separated by the range while maintaining a well formed ML document; determining a reference value, the reference value indicating an association between the start feature tag and the end feature tag; setting the start identifier attribute to the reference value; and setting the end identifier attribute to the reference value.
8. The computer-readable medium of claim 7 , wherein the ML document is an XML document.