Usually, a business’ website is hosted on one web server which is located in a data centre somewhere in the World. For example, the Genius Division website is hosted on a server in London which means the time it takes (latency) for a web page to be served from this server to a user in Sheffield should be relatively quick.
However, if you have users in the US or India which is physically much further away, this latency will be increased and your website will be slower in these locations. To combat this, a content delivery network stores copies of static website files in multiple data centres all over the World. Files can then be loaded from the physically closest location – improving website load speed – which in turn can help with search engine optimisation.