People take ownership in the entire project. Because people take ownership, they will step in and voluntarily help where needed. Since their job isn't done until the project is shipped, people with less work feel compelled to assist others with too much. And people pay a lot more attention to the entire project. If another part is in trouble, the sooner it is addressed, the sooner the project is back on track.
Managers have to keep everyone on the project informed of direction and status.
This is a critical component. Employees are not stupid, at least not the ones at Microsoft. They won't push to do something that won't sell. The team also has to buy off on the proposed schedule for a project. The schedules are aggressive.