18. A method comprising: receiving, from a computer system associated with a reviewer, multiple comments about a word processing document; presenting the multiple comments to another computer system associated with an editor; for each comment of the multiple comments presented to the other computer system associated with the editor, receiving, from the other computer system associated with the editor, an instruction to access the comment, accessing the comment in response to the instruction, receiving, from the other computer system associated with the editor, one or more changes to the word processing document that address the accessed comment, and storing the one or more received changes to the word processing document in a document difference record associated with the accessed comment; receiving, from the computer system associated with the reviewer, a request selecting a first comment from among the multiple accessed comments; and presenting, to the computer system associated with the reviewer in response to the request, the word processing document and a first document difference record associated with the selected first comment, while hiding document difference records that correspond to unselected comments from among the multiple comments.
19. The method of claim 18 comprising: receiving, from the computer system associated with the reviewer, another request selecting a second comment from among the multiple accessed comments and unselecting the first comment; and presenting, to the computer system associated with the reviewer in response to the other request, the word processing document and a second document difference record associated with the selected second comment, while hiding the first document difference record associated with the unselected first comment and any document difference records that correspond to any unselected comments different from the first comment from among the multiple comments.