hi!
if you know well those platforms (i do not), i guess in the wiki docs you can find your answers by yourself, and an installation of the stable 1.9x or better the new 2.0 _beta_ can give you even more details and insight on what really proxmox is, after all it's easy and free!
Anyway, i try to get further. I am not an expert but
http://en.wikipedia.org/wiki/Cloud_computing says:
<<Cloud computing is the delivery of computing as a service rather than a product, whereby shared resources, software, and information are provided to computers and other devices as a utility (like the electricity grid) over a network (typically the Internet).[1]
Cloud computing provides computation, software applications, data access,data management and storage resources without requiring cloud users to know the location and other details of the computing infrastructure.
End users access cloud based applications through a web browser or a light weight desktop or mobile app while the business software and data are stored on servers at a remote location. Cloud application providers strive to give the same or better service and performance than if the software programs were installed locally on end-user computers.>>
so, cloud computing is a way to remotely access computers and data without even knowing their real nature or geographical location.
"cloud platforms" became so popular nowadays, because there is a (more than ever) easy way to provide this easy and cheap: virtualization environments.
PVE stands for virtualization environment, and i think it is not really a cloud platform: it has no facilities (by design) to manage "subscriptions", "on the fly" resource/space allocation, and such. It does not offer connection brokers, resource pooling, because you really don't need that for servers, those are for dynamic clients allocation and more. PVE is much more suited to servers than clients, and that by design. Of course you can virtualize any kind of computer on PVE (openvz or kvm) and you can rach those by VNC, RDP, Spice in the future, so it works like a cloud does, but it is not really made to build a cloud, even the technology is the same, in the background.
PVE has unique features, and many people prefer it to other (commercial or not) VE, and it has a grat and friendly community, which is the best for me...
I hope others will correct me, comment, add and contribute to this, in the end we could make a wiki entry.
Marco
