Today, Dropbox announced that it will allow for collaborative editing in Microsoft Office. While not as seamless as editing a Google doc, it will help users avoid overwriting each others changes and sync those changes more quickly.
Collaborative editing works in an interesting way: When you open a file in Excel, Powerpoint or Word, you'll see a green checkmark on the screen. If your coworker opens the same file, you'll get a notification and can chat with them. If either of you make changes, you can click a button to quickly sync those changes. While this only works with Microsoft Office at the moment, Dropbox plans to release support for many more applications in the future.
These new features will be available soon through a software update.