It's no surprise that Microsoft loves Groove Networks and its product. It's closed source. It's closed data. It's locked to Windows. But all of these properties also mean that Groove is just so old fashioned. I'm not saying the product isn't viable - in fact the few times I've used it it's been pretty neat - but I can't help but wonder how many companies wouldn't rather just use Basecamp for data sharing and project tracking and Skype for voice along side it.
If you want more control there's something like Jot.
For a whole lot of people it's not really important for these applications to be integrated in to one closed data universe. Rather, that's a huge disadvantage. And it is obviously easier to integrate an open enterprise (i.e. one where company, customers and subcontractors talk to each other across technical and corporate boundaries).
When Groove started, these easy to use almost-free collaborative spaces online didn't exist, but now they do and that makes it hard for me to see why Groove will remain interesting.