Some GMs will use color codes to help with this problem, and others may rely completely on the highlighted text. This will be decided on a game by game basis. The best way to ensure that you don't miss any new content, is to click into your game move, and select the author drop down box (ex: #6 Torchwood). Find the last update that you are sure that you've read, and from there, click on each author revision, one by one. Ensure that the checkmark box next to highlight changes is checked and click view revision.

What this will do, is highlight only the text that was touched by that author. Yellowed areas will indicate new content or changed content. Gray text is an indicator of content that was removed. Do note that sometimes an entire sentence or paragraph might be highlighted, even if their change was a minor edit. Skimming for obvious new content will make for good results. GMs that use color coding as well, will find that when they go into the file to remove the codes, it will make for a lot of highlights in the view screen. It is recommended, that they drop the code first, and then do a fresh edit to incorporate any new content. It will help their players find the new content easier.

Some additional notes:

If you expand it you will see a list of recent revisions to the document.

This will allow you to see who added to the game and cycle through each addition with the latest revision at the top.

By selecting a version and clicking the view revision button the text added in that version will be highlighted in the main body of the document.

By cycling through the revisions you can see what each person added.