I can tell you my fortune 500 company cannot touch it even if we wanted to, with customers credit cards and CC Zone rules that have to be behind Firewalls , PCI , financial records of all types, and rules for different States / Countries regarding their citizen's personal data.
Once company data is vetted for what could go not the cloud there's not a compelling argument to use it vs the RISK of eventual intrusion. Yes I said eventual.
Can't even put email there. Too risky
When I think of Lines of business
Merchandising - cloud Vendor/Buyer collaberation on future SKU prices. Nope.
Retail - Transactional Order data / credit card info - even encrypted...NO!
Finance - Goes without saying - Hell No.
eCommerce - Other than the external websites, nope. Customer data.
Warehousing - Sure lets put our pending delivery pipeline in a cloud...
Corporate Support - eMail sure /sarcasm - we got enough lawsuits already.
Business Intelligence/Datawarehousing(aka money sink) - meta data for your entire operation crunched a million ways.
When I look at it, I couldn't even recommend putting "Out of Control" Sharepoint in a cloud.
This is why all of this "WILL occur, because it makes no sense whatsoever...at least not today. and becuase our leaders are corrupt.
Marketecture - Vendors are bright people in general and theirs salesmen are slick...So are the Timeshares I hear about in other countries our former Execs used to visit...freeee.