Cloud hosting is the latest trend in web hosting. Like everything else that uses the word “cloud”, it will be the next big thing that will revolutionize everything that you have ever known and change the face of the earth forever.

Seriously, though, ‘cloud’ simply means that you have various parts, not physically adjacent, that form a single entity. When we talk about “cloud computing”, we’re talking about using resources from various computers to perform a single task. This is the exact opposite of the old mainframe/ terminal model, in which terminals with minimal capabilities used varying portions of one giant computer as needed. To stretch that metaphor: in cloud computing, the ‘mainframe’ is merely the instructions linking multiple computer ‘terminals’ which are doing a varying portion of the work.

Here’s a handy example: Google. When you do a search, you’re not looking through some giant archive that Google keeps at their warehouse. You’re being guided by a surprisingly small application that peeks at everything that is connected to the Internet to see if it has anything to do with your search terms (it’s not a completely accurate description, but fair enough for our purposes). The “cloud” consists of all the computers that are connected to do the single task, i.e., finding you all the sites that have funny cat pictures (or whatever…I’m giving you the benefit of the doubt).

Likewise, cloud web hosting simply means that the virtual server is spread across multiple physical machines. The relatively vague definition can sometimes be applied to “clustered hosting”, where the same content is copied to multiple servers to increase availability or resource use. However, it is more correctly defined as “grid hosting”, where multiple physical servers (a ‘server cluster’) form one single server, in much the same way the power grid forms an electricity “server”.

Cloud Hosting is attractive mainly because it provides website hosting advantages that tend to be very attractive for large-scale business web hosting. The main one is “scalability” — a buzzword thought to be pretty nifty, by the same kind of people who thought it was really cool to say “think out of the box” about ten years ago or “growing the brand” about five years ago. “Scalability” pretty much just means expandability, or how much room you’ll have to grow into when you need it. On a shared server, you can only take up so much space before you need a dedicated server…and then you can only get as big as that physical server will allow before you need another or bigger server.

Cloud web hosting intends to make that a non-issue, as your size is only limited by the size of the entire network (“virtually infinite”, according to most people, but then again Bill Gates said we’d never need more than 640K).

The other big benefit is called “utility billing”, which is the novel concept that you only pay for what you use. This seems to be a big deal only because website hosting services now usually charge for space and bandwidth whether you end up needing them or not (a joke is that if you did use them all, you’d run into worse problems than simply getting your money’s worth from the website hosting company). What this all boils down to is that the web hosting service will keep a meter running on your virtual server; if you get a lot of action and put up a lot of content, you’ll pay more than you will for a simple couple of pages that just sit there.

There’s also plenty of talk about reliability, but it’s hard to tell whether it’s for or against. Web hosting services have always made dubious reliability claims, and there does seem to be some obvious disadvantages to having your data spread out haphazardly across any number of machines. However, the website hosting experts are quick to point out that the exponentially increased resources will make redundancy (for backups, security, et cetrera) that much quicker, easier, and more affordable. So who are you going to believe?

The Major Players:

• The Rackspace Cloud (previously Mosso) — one of the first cloud web hosting services out of the gate, they managed to make all the mistakes that everyone else learned from. Still, they manage to offer some amazing web hosting options that give plenty of control to customers.
• Amazon AWS (Amazon Web Services), also known as EC2 (Elastic Compute Cloud) — very modular, use-what-you-need web hosting; may be more suitable for tinkerers and hands-on types until more user-friendly interfaces are finished
• GoGrid — another of the trailblazers that everyone is watching; the web hosting reviews indicate a combination of AWS flexibility and Rackspace (semi) user-friendliness, but can get pricey on the meter
• ElasticHosts — the first UK and also the first Linux-based cloud website hosting platform. Not much feedback yet, but more good than bad so far.
• OpenHosting — seems to be perfect for a specific subset of knowledgeable but also hands-off types, not infinitely scalable but not expensive either.
• SliceHost — now part of Rackspace, only time will tell what real difference there will be between the two. For now, similar to OpenHosting
• GoogleAppEngine — always seems to be about to get much better. Hard to judge web hosting overall, with so many paths and options available.
• 3Tera — well-marketed but quiet on the review front; seems to outsource to various web hosting partners. Possibly a ‘wait and see’ situation.