Collaboration for the offline worker has always been a challenge. Personally, I was a big fan of the Lotus Notes model of syndicated databases to ensure data synchronization for offline use. Unfortunately, Lotus had a terrible user interface and a poor marketing message. Microsoft's recent acquisition of Groove and the inclusion of Groove's founder Ray Ozzie (the original brain behind Lotus Notes) into the Microsoft leadership team is a great move on their part...I'd expect to see Groove tightly integrated into the next version of Microsoft Office (Office 12).