The document is kept on the dropbox servers, in a folder that can be accessed and modified by all collaborators. I cannot recommend this for projects where you foresee lots of editing.
Also, people forget to download the email attachments sometimes, or download them into the wrong place, etc. I have seen it used a few times my impression is that it works well when there are few authors and few changes to make and the "baton" doesn't change hands too often but once things get complicated, it's a matter of time until confusion arises as to who is holding the "baton". The biggest disadvantage of git is that people have to learn it (naturally, combinatorialists and computer scientists have the easiest time doing so), and that merge commits are confusing (I think, even to experts - try debugging a merge gone wrong!).Ī classical tactic, mentioned by is the "editing baton" (i.e., at each moment, at most one of the authors is editing the file, and the others are made aware that they should not be making changes once done, the author emails the new version to all collaborators). I also found it very helpful when responding to referees - with a clean history, I can easily list all my changes between two given dates. Also, branching allows you to experiment and make edits that your collaborators won't like until they see the final form, without raising the ire of your collaborators for (temporarily) messing up the work. But it removes various dangers such as losing your changes because your collaborator overwrites them, and it makes the history of the document readily available (though, in order to see the changes on github, your lines shouldn't be too long - standard "mistake"). Now, git isn't magic - it will not guarantee that everyone writes in a common style, or that notations match it will not resolve your disagreements about good writing it also will not merge changes made in parallel to the same piece of the text (it will only alert you that such conflicting changes exist). Example with 1 author (it's useful even then). The "cleanest" and safest option is a git repository (on github or gitlab or bitbucket or, the good old way, on someone's server). For writing the LaTeX document, here are several options I've seen used: