Probably the only thing I like about Word is the Track Changes feature. Once you turn it on, you can track all changes you make to a document, and when you have multiple co-authors editing, this can be handy when attempting to resolve disputes. Also, often what happens is that I make some changes that my co-author doesn't notice because they are buried deep in the middle of a section, and it would help to have some way of marking these up.
Most people I know have some kind of \note mechanism for making margin notes, but that doesn't help with changes that you know you want to make, but also want the co-author(s) to look at. Does Emacs/LaTeX have macros for tracking changes in documents ?
p.s for those of you who will immediately write in suggesting that I use CVS, remember that I am behind a firewall, and even if I weren't, CVS is a heavy hammer for something as simple as this :).