The pre-announcement is the more significant news. When the next version of Office for Mac ships "in time for the 2010 holiday season" (so the name Office 2011 seems a fairly safe bet), Entourage will be replaced by Outlook for Mac.
We can hear many business users sighing "not before time." One of Office for Mac's biggest weaknesses - if you ignore Office 2008's VBA-ectomy, but we already know that's coming back in the next version - has been inadequate integration of Entourage and Exchange.
What's been disclosed so far is that Outlook for Mac will use Apple's Cocoa frameworks, feature a high-speed file-based database that will integrate well with Time Machine and Spotlight, and (along with the other Office programs) support Microsoft's Information Rights Management scheme.
One of the issues with Entourage is that it stores the user's data in one large database file. This has some advantages (eg, it reduces the amount of wasted disk space), but does not sit well with Time Machine or Spotlight.
Microsoft delivered Spotlight compatibility with a scheme that generates proxy files containing the text of (eg) messages. These are indexed by Spotlight, and when they are opened cause Entourage to display the real item. It works, but wastes disk space by duplicating information.
How will Outlook deal with these problems? Please read on.