Reliability. With cloud hosting you may experience a bit more downtime then a dedicated server. There are too many outside variables for me to switch. Plus, when something goes wrong, I have the server to fix the issues, rather than emailing and calling until someone answers and someone can fix the problem.
That is a strange perceiption, but depends what the OP and you are meaning with "cloud". There are many cloud service providers who don't talk about cloud by simply datacenter, but by the technology they use, meaning real cloud computing engine.
With a real cloud computing engine (Openstack, Cloudstack etc.), you get the highest availability ever, and beat dedicated servers by many times. The service is decoupled from the underlaying hardware, means any hardware downtime won't affect the service.
Alfons
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Alfons Meier - af[at]vpspace.com
System Engineer at VPSpace.com Premier Cloudstack Real Cloud Service Provider
Cloud hosting is often a solution for web sites that have outgrown the resources of their existing shared hosting provider. If a web site is extremely popular and causes a strain on the resources supplied by a shared server, you may need to find another solution. Often this solution is dedicated hosting where your site resides on its own server. The problem with dedicated hosting, though, is that it is both significantly more expensive and requires a certain level of IT know-how. With cloud hosting, you can have many of the advantages to dedicated hosting without most of the challenges
Cloud hosting services provide hosting on virtual servers which pull their computing resource from extensive underlying networks of physical web servers.
It is built, hosted and delivered via a cloud computing platform via the internet, and can be accessed remotely. They are also known as virtual servers. Everything is on internet so there is less chance of downtime.
Cloud hosting is a kind of web hosting which uses several different web servers to stabilize the load as well as maximize uptime. As opposed to utilizing a single web server, your website can take advantage of a "collection" that utilizes sources from a central pool. This means that even if one server falls short, another starts to maintain every little thing operating.
Visualize the cloud as a web of various computer systems which are all interconnected. As more makers are hooked up to the network, even more sources are added to the overall cloud.