The section i found most interesting from pages 57 - 69 (Writing Collaboratively) was about critiquing a group members work. Even if if the intent his not to be rude and the rules listed on page 68 are followed through 100%,  you cannot disregard the human factor. When some one is putting their work out there for some one else to view its very easy to take every little critique as a personal attack on their spell, grammar, skill (at typing), or even intelligence. Considering the book states that " Knowing ho to [critique notes] without offending the writer is a valuable skill" it does not spend much time on it.