Cloud Computing is the computing resources like hardware,software or application delivered over the internet.

There are 2 types of Cloud

1.Private cloud
2.Public Cloud

Private cloud is also called as internal cloud in which organization owned network or a datacenter that supplies hosted services to a people limited to that organization basically within the firewall network.

Public Cloud is the service in which some organization sells services to anyone who requested it over the internet  Amazon is one the provider for largest public cloud  Hosting.

Virtual Private Cloud is service provider uses public cloud resources to create their private cloud in other terms, private cloud existing within a shared or public cloud.

TOP 10 Cloud Hosting Providers in 2012 as per SearchCloudComputing.com

1.Amazon Web Services
2.RackSpace
3.CenturyLink/Savvis
4. Salesforce.com
5. Verizon/Terremark
6. Joyent
7. Citrix
8. Bluelock
9.Microsoft
10.VMware

Below is the list of other “Private Cloud hosting”

1.Firehost
2.GoGrid
3.ElasticHosts
4. SingleHOP
5.Cloupia
6.Fusepoint
7. Amplidata
8.WSO2
9.Intalio
10.VMware Vsphere
11.3X.com
12.CloudSigma
13.Softlayer
14.GODaddy

Thanks For Reading !!!!