The cloud is a wildly inaccurate metaphor, a marketing buzzword, and a legitimate approach to web hosting.
Web infrastructure providers have access to vast amounts of computing power — nearly countless stacks of server hardware and storage, connected together to form amorphous computer networks that can act as a giant supercomputers, and which can be then partitioned off into virtual computers of highly variable size and configuration.
This is "the cloud." It's a wildly inaccurate metaphor because there is nothing cloudy about it. It isn't a weightless mist of computer ability — it is stacks and stacks of very real computers, in gigantic air-conditioned rooms, connected together with copper cables and fiberoptics.
The cloud is also a marketing buzzword. Web hosting companies like to use it to cover over the fact that they are just renting their computing power from another provider — often from one you could rent from yourself for less money. Software companies sell software as a service subscriptions on top of "cloud based" infrastructure because it's cheaper for them, but they market this fact as if it seriously makes a difference to you, the end user.
All that being said, cloud computing is a completely legitimate approach to web site and web application hosting.
If you are building a new web application, or a for profit web site, and you need it to be able to scale up to handle large amounts of traffic, the most economical solution is probably to use cloud hosting. Because your site or app is being host on a virtual machine, running on top of a variable pool of computing power, cloud hosting makes it easier to increase or decrease the amount of available power as needed. This can keep your site running no matter what kind of traffic you experience, and can help keep your expenses down by allowing you to only pay for what you use, and only use what you actually need.
Cloud hosting is a type of web hosting where a Virtualized server (similar to those available in VPS hosting) is run on top of a variable pool of computing resources (a "cloud"). This allows you, the customer, to scale up your available computing power as needed.
Many (but not all) VPS hosting plans are actually cloud hosting plans, whether or not they are advertised that way.
That depends on what you are trying to accomplish.
If you are setting up a personal blog, or a website for a small non-technical business or local non-profit, you may be able to do everything you need on a shared hosting plan.
If you anticipate high traffic numbers, and you need to be able to scale your website's capabilities quickly, then you might benefit from a cloud hosting plan.
From a user perspective, a cloud-hosted website isn't very much different than a conventionally-hosted VPS hosting plan, or even a shared hosting plan.
To find hosting companies that offer cloud-based plans, use our hosting features tool to compare cloud hosting plans.
Check out our list of hosting companies that provide cloud hosting.
SaaS is an acronym that means "Software as a service."
Usually, SaaS refers to subscription based applications in which a software application is accessed remotely via a web browser or other local client. The service provider maintains the application, and the customer doesn't need to install, upgrade, or maintain the application on their own local computer.
For an example of Software as a Service, consider the two different ways you can use WordPress:
One the one hand, you can run WordPress yourself on your own shared hosting or VPS hosting plan. You control your hosting, and you install WordPress on it yourself. This gives you complete control over how you run your site and what you do with it.
On the other hand, you can get a free blog at WordPress.com. You don't have to install the software or worry about upgrades. It's easier, but you also have less control over your site and your content. WordPress.com is a SaaS application.