What's the deal?
According to this announcement, you will now be able to edit Microsoft Office files from Dropbox's mobile apps, access Office files stored in Dropbox from Office mobile and web apps, and share files directly from Office apps.
But there's a caveat
You will need Office 365 licenses to be able to take advantage of this integration. Regular Office licenses won't do.
What's in it for Dropbox?
Dropbox has been immensely popular cloud-based file sharing and sync service, especially for consumer-centric scenarios. In fact, Dropbox has served as something of a bellwether in this marketplace, and continues to influence many other tools in terms of functionality.
However, Dropbox has presented difficulties within enterprise environments, especially those that require sophisticated controls and need to support complex business processes.
To be sure, the vendor's current offering for enterprises -- Dropbox for Business -- is now in its second incarnation (first one being Dropbox for Teams). But it still has functional limitations for use within enterprises, especially larger ones. for example, a subfolder inherits permissions from parent folder and you can't give a different set of permissions to a subfolder. This means it could become very difficult to create different sharing schemes when you have large number of people, teams and folders.
Perhaps this partnership with Microsoft will help give Dropbox an additional push within the enterprises. If you're a customer with large Office deployments, don't just ignore Dropbox's functional limitations because it now comes with a "Microsoft partnership" badge.
Another interesting aspect here is that Microsoft already promotes its own cloud-based file sharing and sync service known as OneDrive. In spite of that, they went ahead and partnered with Dropbox. This seems indicative of the continuing power and autonomy of the Office team as Redmond's key profit driver.
Finally do remember...
... that a lot of other cloud-based file sharing and sync providers also provide some level of integration with Microsoft Office applications, mostly via exposing their storage as a set of WebDav folders that you can directly access from client applications, including Office applications.
So if you are considering this combination, make sure you evaluate enterprise considerations such as Integration, Security, Administration, and so forth besides this linking of Office and Dropbox. Our ECM & Cloud File Sharing vendor evaluation research can help you here.