Further to my blog last week on the difference between traditional outsourcing and cloud computing, I've received a deluge of comment and information. I couldn't possibly hope to include it all in one blog (or even two or three), but I'm passing on many of your emails to my colleagues at sourcingfocus.com, who hope to cover the subject in more depth in the coming months.

But I'd still like to share with you a sample of the insights I've received. Perhaps the most useful discussion came via an email 'chat' with Gary Barnett, partner and chief technology officer at research and consulting firm, the Bathwick Group. My thanks to Gary for his thoughts on this issue.

Part of the problem with cloud computing, he says, is that currently, it means "everything to everyone". Instead, it helps to think of cloud computing as a spectrum. "At the one end, you have full service provision; then software-as-a-service (SaaS); then utility computing - companies like Amazon with its EC2 platform that offer 'computing cycles' as a utility service," he explains.

But whether it's SaaS or utility computing, he says, the 'cloud' element implies a level of automation and virtualisation that hides the complexities associated with scaling usage up and down - a capability that he refers to as 'elasticity of supply'.

Outsourcers should be very interested in the whole spectrum, says Barnett. "At the service provision end, Kris Gopalakrishnan [of Infosys] is right to see both threats and opportunities. SaaS is the best way to reach down into the mid-market when it comes to offering services like managed email, customer relationship management (CRM), enterprise resource planning (ERP) and so on."

"At the utility end of the spectrum, meanwhile, outsourcing providers can exploit the technical elements of cloud (automation, virtualisation, elasticity of provisioning and so on) to deliver more cost-effective computing services to their clients, or more importantly, to provide clients with a clear idea about how the outsourcer is going to get all the efficiencies they promise."

"Most of my end-user clients won't be 'going to cloud', in the sense of moving their apps/infrastructure to cloud-based services," he adds. "Instead the cloud will 'come to them' - they'll buy in services that are delivered on the cloud, or an outsourcer will gradually transition their infrastructure to cloud as part of an outsourcing deal. Sure, some new apps will be developed for cloud - but there's a heap of legacy equipment in End-User Land that isn't going to shift to the 'cloud' any time soon."