Geek In Disguise

I can see some point in a private or exclusive cloud where a service provider wants to guarantee performance and capacity.

The private cloud becomes more than a WAN because there's shared capacity and a potential common interest amongst subscribers something akin to the mediatone network offered by WebEx, today it still has its place.

It's a traditional approach to networks rather than engineering adaptive capability in software and you are right these providers for the most part don't have applications optimised for the 21st century Cloud.

the question is should these closed communities of interest be serviced by virtual private clouds within the public cloud or band together to provide their own private infrastucture? I suspect in the current internet ecosystem and the gathering pace of multi megabit home connections the only way to be sure of your environment is to take a private cloud approach.  

I've been doing some work for a 'security as a service' cloud vendor recently. What's interesting about that model is that large, multi-office companies get a real saving by consolidating all the web and email filtering with a cloud provider rather than replicate on-site systems in each office (or at least in each location where there is an Exchange server). However, companies give up a fair amount of control over their infrastructure when they outsource this way. This is a legitimate trade-off and is probably beneficial. However, in this sort of situation, you could imagine that a 'private cloud' could give these companies the benefits of outsourcing over the internet combined with the enhanced control of in-house systems. Still, I think this scenario is still somewhat hypothetical. It'll be interesting to see if security vendors start popping up offering MessageLabs-like services in a 'private cloud' configuration. I'm not sure there are any yet but I could be wrong.

Why are you doing this hidden url crap? Just post http://gigaom.com/2009/04/11/6-half-truths-about-the-cloud/