I just read an interesting blog titled "Risk Management and BI Cloud Computing – Will It Work and Who’s in Charge?" authored by an old IDC colleague, Bill Peterson. He makes some very valid points, but doesn't really describe how they should be addressed. I suspect that is because of space limitations he faced when writing the post.
In my view, security is a critical component of a successful cloud computing implementation regardless of the company size, the vertical market it plays in or what workload or application is living in the cloud. In the world of business intelligence, this translates to risk and risk management.
Security is one of the four pillars of cloud computing in The 451 Group's CloudScape Codex.