Since the beginning of my company's project, we've in mind to build work flow into the system. We've review a few workflow system vendors and it just doesn't seems to suit us as it would require us much customization work and with limitation.
I believe the market for workflow applications is increasing and it does have a direct impact on the efficiency of a business. That would tells why Microsoft is coming into the stage now.
To be released together with WinFX, the Microsoft Windows Workflow Foundation is now available for preview as well as tryout.