In my view, the idea of cloud computing is perhaps one of the most exciting new directions the IT industry has taken in a long time.   And it's becoming more real every day - as evidenced by  recent announcements, with of course a lot of opinions on how it might work out.   The realization that the Internet allows most computing to be performed elsewhere or "in the cloud" is a marvelous advancement from the perspective of the end user.  The other side of the cloud is a different matter.  There are a host of opportunities and complexities that must be provided and managed in alignment with the very different business models of those who provide the computing "beyond the cloud".   Its worth mentioning that cloud computing has been closely related to the grid computing model   (although it is distinct) or utility computing. 

If we step back and look at larger IT landscape, there are several identifiable trends that are helpful to understand:

Briefly, from the bottom moving up:

• Traditional DC: a rigid or perhaps purpose built model with a low degree of automation. It may be too strong to say that this segment is declining, but it is not growing at the rate of other motions.
• Virtualized/Consolidate: An extension of the Traditional model, but using virtualization as a means of consolidating and save cost. This is indicative of an organization that is continuing to keep abreast of some technological developments but still may not be on the growing edge of IT.
• Virtualization for Agility: In an attempt to get the greatest return possible on IT investments, those who use virtualization as a means to rapidly change or evolve their IT in support of their changing business model will excel.  There is much growth and opportunity here, but it is not without complexity and potential expense.
• Cloud Computing: This is the last motion I will mention (while there are at least 3 additional motions that may evolve as things progress) it is our current focus using web services to focus on flexibility and OpEx

Cloud computing I believe represents the greatest opportunity in the foreseeable future and may in fact become the basis for most modern IT services in the next few years. 

As we begin this journey, I propose that we create a clean definition upon which we all agree and hopefully create an architecture reference model for it.  I certainly don't want anyone to post anything they feel contains their IP or the key to their business, but such a vehicle will create a common reference and the opportunity to evolve the industry in the direction we want to see cloud computing evolve. 

Here's my take at a definition for Cloud computing:   packaging of computing resources in a manner that will provide lower acquisition cost of hardware, packaged in a way that provides a set optimized services to the end user via the Internet in the most cost-effective, operationally efficient means possible.

The team here is looking forward to a good discussion on Clouds and where they're headed so please jump in...