NIST definitions and powerpoint on Cloud

2 great documents on cloud posted in the document section of this community.

1. NIST updated definitions on Cloud Services can be found here. This is the godfather’s set of definitions of cloud
2. NIST updated presentation on Cloud Services can be found here. This presentation includes a section on security, and besides the security challenges on cloud, it also lists the security advantages of cloud. The presentation includes some interesting case studies (for ex GE moving 400,000 desktops to Google Docs / Zoho) and some references to Cloud economics and statistics. Very good primer is you are completely new to Cloud

The original files can be found at: 
http://csrc.nist.gov/groups/SNS/cloud-computing/index.html
NIST is the US National Institute of Standards and Technology.