From "where cloud computing is going" to "what is": somewhat back to front. But a recent article (Twenty-one experts define cloud computing) in the Cloud Computing Journal pulls together the thoughts of a number of people, which can be usefully condensed here.
Bearing in mind that although it is evolving from the business environment to the personal, the concepts are similar. Although it might seem that business-level infrastructure needs simply don't apply at the personal level, history has already amply demonstrated the blurring of this demarcation over time.
Cloud computing is all about "elasticity" [Amazon]: with your software, data, environment and resources all available via the internet, you can scale your computing infrastructure on demand, to take effect more or less immediately. This avoids under-utilisation (investing more than you need to) or over-utilisation (choking) inhouse. Ideally, resource needs automatically scale to meet current demand [Markus Klems]. Although in theory this can massively improve resource efficiency, in practice it may just mean overall capacity keeping pace with demand.
Omar Sultan likens it to extreme flexibility with meals. You can cook at home, you can order in, you can change at the last moment, source missing ingredients, feed each family member whatever they prefer to eat.
Resources here can refer to software as much as hardware. At its extreme, it may imply only paying for the amount of use you make of software, rather than buying it (eg MS Office) upfront [Jeff Kaplan]. Some applications are already achieving this, albeit with different funding models. Think Google and Facebook. As opposed to incremental purchase, prepaid or postpaid bills, an alternative, more manageable, payment model can be advertising-based - the true incremental price mechanism.
And it does away with the cost - in both time (hassle) and resources (money) of managing one's computing needs oneself [Jeff Kaplan]. You don't want to, don't need to know how or where the resources are managed - that management has been sufficiently commodified that you trust your service provider to manage your resources better than you would yourself. In fact, your service provider would maintain a similar efficiency by managing the elasticity with the help of outside resources - effectively, service provision for service providers [Kevin Hartig].
An especial appeal to the consumer in this would be to hide the complexities of I.T. [Irving Wladawsky Berger]. Too easily, access to information storage and processing becomes the province of those best in the know. For example, this can marginalise someone who has a very powerful imagination yet is not - by choice or circumstance - computer literate.
But above all, it means portability of one's information and knowledge: that is, the totality of one's computer data, environment, and resources. Any device, anywhere, can be used to access your environment and data. It's all portable. You can hire an end-device (laptop, PDA) by the hour, simply using it as an interface to your electronic world.
Some commentators are saying "what's new about this", which is a fair comment in some ways, but this could also just be hindsight - in 1988, few would have had the imagination to think it could go as far as it is going. Others are saying it's overstated, we won't need or bother with most of this. But it's just imagination they lack...
It is not there yet; half of this is anticipation. But the time will come when we will be able to "just do it", anywhere, anytime, without needing to care about the grinding, quotidian detail.