Phase 3 is the most interesting part of the Gutenberg project for me personally.
Phase 3 will allow multiple users to interact with WordPress content at the same time. This is the Google Docs experience inside WordPress. Open up a document, click a button and share that document with others. Those with the correct permissions can interact with you in real time, and you can see the amendments they’re making in real-time.
I chatted about Phase 3 with Nathan Wrigley at WPTavern. We talked about why this a necessary update to WordPress, but also why it’s such a difficult feat of engineering.