Cloud computing 360 degrees

I needed to present the implications of Cloud Computing and how my company could take advantage of it. Here's a brief primer on different things I considered while giving my judgement.


Types:
• Private Clouds (used by big enterprises)
• Public Clouds (used by SMEs )
• Hybrid Clouds (used by big enterprises and service providers).

Characteristics:
• End user doesn’t own any of the infrastructures. For private clouds you do own the infrastructure –however these are different set of players and rules of the games are different here.
• Pay as you use instead of straight-away renting infrastructure from a 3rd party.

What can a Cloud do OR what are the manifestations of Cloud:
SaaS: examples of Gmail, Salesforce
Paas: Solution Stack, like say LAMP , Microsoft BPOS.
Iaas: Providing entire infrastructure that one may need to run a datacenter. Eg: Amazon & 3Tera
Pros:
• Zero to near zero capex
• Device and location independence.
• Shared infrastructure & costs
• Low management overhead.
• In theory you can cancel the contract and stop paying whenever you want with absolutely no overheads.

Cons:
• High opex.
• Security a major concern, since data is stored on infrastructure owned by someone else.
• Technology/Software locking possible.
• Highly dependent on the service providers.

What market leaders say:
• Companies like Google, Microsoft, HP, IBM are pro-cloud computing. They are developing products/service models around cloud computing.
• Richard Stallman (creator of GNU and Open Source) & Larry Ellison (CEO of Oracle) strongly oppose cloud computing on basis of security concerns. Larry Ellison thinks Cloud Computing is just a new term for already existing infrastructure.