You'd think, wouldn't you, that version control and genome annotation go hand-in-hand. Yet a web search for those terms throws up very little.
One approach might be to use a wiki, e.g. the popular MediaWiki. Wikis feature version control, they often have plugins that allow extensive customisation and they have been used in other biological curation projects.
Some genome projects employ other tools for community annotation. A good example is the Paramecium project, which uses tools from GMOD. I'm unsure to what extent version control is employed.
The main web-based annotation software package that I know of is Manatee. It can store "old" annotations alongside "new", but I don't think it does true version control. It also requires quite a bit of administration to install (apache, mysql, multiple perl modules).
If you do want to go with just basic RCS, I think git could work. Subversion has a central repository, but anyone with rights could upload to it without notification. Using git, people could work in their own way then submit a pull request, which other members would approve before incorporation.
would something like Dropbox work? https://www.dropbox.com
Not really. It need to be concurrent for real, in the spirit of git. In such a way that we could test and commit versions of the annotated genome made with rather different pipelines.
I vaguely remember attending a seminar from an OBO/ChEBI curator who was explaining how do they were doing the annotation versioning. However, I can't find any link to this now... I am sorry, it was really a long time ago :-)