A public cloud is one based on the standard cloud computing model. Resources such as applications and storage are made available to the public over the internet by the service providers. Public cloud services may be free or offered on a pay-per-usage model and by using software as a service (SaaS) reduces ownership cost.
Comparing cloud computing with dedicated hosting comes up with mixed responses. The advantages of cloud include low cost, fast provisioning, easy manageability and high scalability. We don’t have to worry about the initial set-up cost for the hardware or software for loadbalancing as these are managed by the cloud computing platform providers
The major concerns about public cloud include - Data privacy and integrity, Service availability, Moving data between service providers etc. Since public cloud computing is available to anybody, the concerns about the risk of security breach is high. This is where the Private Cloud overtakes the Public Cloud concept. While public Cloud is offered as a service over the internet, the private cloud is a deployment within a firewall and is maintained by the concerned enterprise. Public cloud’s advantage includes low upfront cost and infinite scalability while the main concerns are with accountability, security, and lock-in.
Some of the main public cloud providers include Amazon Web Services, Rackspace and GoGrid.