Computerworld has an interview with Ray Ozzie of Groove:
When we started Groove in ’97, it was largely based on a viewpoint that the nature of business was changing not just the organization, but that business itself was restructuring from big, vertically oriented corporations. It was becoming more of a mesh of companies interacting with one another. This was based on my experience of what people were trying to use Notes for and were having a hard time doing, in terms of deploying Notes across organizational boundaries.
So Groove was based on the fundamentally changing nature of business. Essentially, what we’ve learned in the past few years of people using Groove is that it’s not just the nature of business that’s changing; it’s the nature of work itself that’s changing. You’re working with multiple companies, and you’re working with people in a geographically distributed manner. You’re working at home and in the workplace. The trend of decentralization that Notes started within the corporation is moving between corporations, and now it’s touching individuals.