Best tool for screenwriting collaboration
There are two aspects to consider when thinking about the best tool for screenwriting collaboration. One, what aspect of screenwriting are you collaborating on? Are you in a writing team? Are you taking turns writing? Or is it a notes process? This is a major consideration.
Two, how much control should each collaborator have? Are you giving people the right to modify your work or just view it and make notes?
Using your screenwriting software.
The most popular version of file sharing is Google Drive. You can upload your file (in this case your script) and send people a link. This is good, but lacks some of the collaboration that I think you will need as a writer. You could always create a Google doc and allow people to leave comments in that. Using this enables people to see each other’s comments as well.
If you are into more involved collaboration than just file sharing I would say WriterDuet is a great choice. I have to be completely honest here, I have used it for years. I am in Australia and the producers I work with are all overseas. Therefore, being able to share files and even enable them to make edits is great. Side Note: They are about to release a new product. I have my hand up as a beta tester. It will allow more control over who can see your work as well as version control and notes. Depending on how good it is, it may make the rest of the article obsolete.
A step beyond Google Drive
I would suggest you set up a slack account (slack.com). This platform is specifically designed for collaboration.
How to configure SLACK.
Think of Slack as a series of chat threads where you can comment, add pictures and other files in an endless timeline for access by a single team. I have configure Slack in this way.
I have the General Thread, this is like a news room. The anything goes chat space. I then have a thread for the script. I post new versions here and people can make notes under the new version. We discuss the script and can see who made what suggestion. This is very helpful to make sure everyone is informed and on the same page. It prevents the quiet side conversation which will derail true collaboration
We have a thread for each character. For a small production (such as the one I am working on at the moment), it is great to see who is being suggested for each role. Once we have the cast member locked in it is noted in the thread. I can then customise story to that actor if needed.
We also have threads for other topics such as location and schedule. The other thing that Slack provides is private chats. You can have an ongoing conversation with anyone in the Slack.
Slack biggest Pros.
The single biggest pro for Slack is version control. People can go to the script thread and have the most recent version. They can also find older versions if they need to reference them for some reason.
The other benefit is no more long email threads, or missed emails. Everyone has access to the same information at the same time. Especially if they have notifications turned on.
This may seem like an advert for Slack, it is not. I have found it a huge benefit to communication and productivity. If you are about to make a film of any size, get onto slack. It has an app for both iPhone and Android and it will make your production so much easier.