Compare between different formal Cloud definition? Based on stale and standards? (include the NIST definitions)

Compare between different formal Cloud definition? Based on stale and standards? (include the NIST definitions)

Hint: SP 800-145 September 2011  The NIST Definition of Cloud Computing

write briefly on Cloud Computing Recommendations suggested by NIST .

Hint:  SP 800-146 May 2012  Cloud Computing Synopsis and Recommendations

What are the Key Security and Privacy Issues?

Hints:  SP 800-144 December 2011  Guidelines on Security and Privacy in Public Cloud Computing