It's not out yet (due to launch this spring, which is now officially over today). Some fabulous built-in collaboration tools, including real-time commenting by multiple contributors.
In a blog post, they talk about design:
It’s not just an obsession with making things look good, but it’s the belief that good design enriches life, that design matters. It matters that the look and feel of an application support the work. It matters that the person at the keyboard enjoys the experience, that they have fun using the tool. We’re providing the writer with a work environment, and we want it to be a compelling, enjoyable place to be.This looks much nicer than Google Docs.
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