Shift the mindset
Judith. Great points about how IT has to take a lead role in breaking down a lot of the siloes that are popping up in business units (or at least establishing an understanding of where they are and what is in them in case an enterprise app needs to access that data down the road).
I'm sure that some smart companies are already approaching this problem. However, I think that for a lot of companies there remains a problem with the IT mindset that presents its own barrier to an enterprise cloud strategy. For many years the attitude toward business units contracting with their own cloud services has been for IT to just say "no". Of course, the result has been the rogue IT groups that have popped up in the business units.
I believe that the IT group of the future not only will embrace the cloud but will take a proactive approach to searching out cloud-based solutions for their business units, and serving as matchmaker, looking at the business challenges and leading the search for safe and effective cloud services to address those challenges. At the same time, they can integrate the resulting data into the enterprise data management plan. The IT groups that cling to their anti-cloud attitude will continue to be bypassed.