Actually, this de-emphasized HELP suggests to me that Microsoft believes the new ribbon interface is so clear that you won't need help. And secondly, that if you need help, you always have a broadband connection. I'm not sure both assumptions are true.
Anyway, here is the answer to the question I received from Microsoft's rapid response team:
"...the question mark button does, by default, take the user to Microsoft Office Online for Help. But if you click on the “Connected to Microsoft Office Online” button at the bottom of the box, you can choose to “Show Content Only from this computer” and that allows the user to see help content when not connected to the internet.
Super Tooltips, a feature of the Microsoft® Office Fluent™ user interface in the 2007 Microsoft Office system, integrates Help topics into the product in a new way to make the experience easier for new customers. One of the main problems that people have with Help topics today is that they don’t know the terms used to describe features. Super Tooltips are integrated help tips that provide quick access to information about a command directly from the command’s location in the Office Fluent user interface. One of the biggest innovations that began with version 2003 was the opportunity to get feedback on our Help. We use this feedback to drive the development of new content and to update current help topics as needed. We also use the feedback to identify trends that assist us in creating better Help for new features. The 2007 Office system Help was developed with the benefit from having feedback from thousands of Office customers."So if you think to go to the bottom of the HELP box, you'll figure out how to get information without being online.