Hosting is the thing that makes your website visible on the internet, and it provides crucial services, like email
If you've bought "mycompany.com" (a domain name) it will sit around doing nothing until you give it a hosting package. And there are thousands of hosting packages available all over the world.
The hosting package you choose will control the amount of space you're website is allowed for storing images and your blog posts and of course your web pages. Crucially, it may also limit the number of visitors (traffic) your website is allowed to handle (bandwidth), and all aspects of your email addresses. So as you can see, hosting is VERY important, so much so that we wrote about why web design is second to hosting.
It's not just about all that either, the speed at which your website responds is vitally important too, not just for visitors but for search engines, and this is also controlled by hosting.
How it works
All the files and images that go to make up your website are put onto a server (which is just a version of the computer on your desk) which is connected to the internet. Your website wont be the only one on that computer. There could be 1,000 other websites on the same machine, and they're all competing for memory and disk space and bandwidth.
The best hosting companies keep this sort of contention to a minimum in order to maintain performance, so if your website is sat on a server with 600 other websites it's obviously better than if it's on a server of the same specification with 1,200 other websites.
This server together with it's resources and various connections is called a 'hosting platform' and it (or possibly another one on the hosting company's network) will also look after your emails unless you've made other arrangements.
How many emails you can keep, how you access them, and the size of your whole mailbox is limited by your hosting package.
What to look for
First and foremost, don't be tempted by free hosting, if you're running a personal website for family and friends you might get away with it, but if you're running a business forget it. Good basic business hosting is far from expensive, and it's something that shouldn't be scrimped on in this day and age.
Secondly, if you're in the UK, get UK based hosting. I know that in the internet world theoretically it doesn't matter where you are, but at the end of the day if your website files are sat on a server in Seattle your UK users are having to wait for their requests and responses to do a 9,600 mile trip and hoping all the routers and stuff are running ok along the way. Get UK based hosting.
Lastly, bandwidth, web space, and reputation are the key things..
Many hosting providers will limit bandwidth, in most cases the limits are actually fairly generous.. A small business website shouldn't normally exceed a 3Gb limit. But we worry about these limits.. What if you post something that goes viral, or you hit a niche for a product and it goes mad? You don't really want bandwidth limits unless your website is a secondary afterthought for you.
Look at the amount of webspace your website is allowed, you might see 500Mb, 1Gb, 3Gb etc.. A small business website might sit happily on 500Mb webspace, but if it's a content management website and you're uploading images and videos you can reach the limit, especially if it's an ecommerce website. So, if you're serious about your website and/or you have an online shop, go for unlimited webspace.
We can't really provide a definitive comparison of hosting companies based on reputation here, there are thousands of articles on the net about it, all we can say is that since 2003 we have used and had experience of many hosting companies both UK based and international (calls to the US and Brazil at 10pm don't go down well) and after some painful and expensive adventures in the early days we settled on Heart Internet. They continue to provide everything we and our customers need, but use Google and talk to business associates, it's an important decision so you would do well to take time over it.
There are some very attractive hosting deals out there, especially overseas, but if you're looking to save a few pounds here and there, trust us, for the sake of a few quid hosting is not the place to do it.