US Patent 10452770 System for tracking comments during document collaboration

A computer-implemented method of online collaboration on a document includes converting a source document from a document generation format to an independent file format, generating a coordinate map for displayed elements of the source document, displaying text of the document to a commenting user in the independent file format, allowing the commenting user to select and comment on the text, matching the displayed text and the comments with the source document using the coordinate map to generate a difference map, and storing the comments and the difference maps external from the source document.