As your WordPress website starts getting popular, you will need to ultimately know what is CDN. This basically stands for content delivery network. I know it sounds a big technical but i will try to explain in the simplest possible terms.
What is ?CDN
We understand that websites are hosted on web servers with web hosting companies. These servers have limited resources based on the type of web hosting you gained. Even the most powerful of webservers has some capacity limits. Every page requested by a visitor to a website is generated by that web server and is presented to the user. This page generation uses resources and in case of a big surge of user traffic, the web server might reach its limits and the website may crash or a poor response time might result at least.
Since the web hosting server has a location, it is very natural that visitors to a ?website that are nearer to the server location will get faster speeds because of the proximity of the server. And those at far away locations will see a comparative slower page load speed.
Why You Need a CDN
This brings huge boosts for page speeds and any unexpected surges in traffic are also managed well because the page load is distributed among different servers and the main server hosting hosting the whole website does not crash. And this also means SEO benefits for your WordPress site because Google loves the pages when they load really fast. However, one thing you should know clearly that you will still need to have web hosting for Content Delivery Network to work.
Who Should Use CDN
A CDN is not for everyone. First of all you should start thinking about using a CDN when your website has started to get really popular. Normal website traffic of a few thousand visitors a day does not need any CDN most the time unless your website is a real money maker with this traffic and you need to further get SEO benefit by improving page speed and improving user experience.
A CDN is considered only when the website is getting hugely popular because then you need to decrease load on the main server to improve page load speed and user experience.
Is CDN Difficult to Use
CDN is not difficult to use at all. If you are using a WordPress Caching plugin, then setting up CDN on WordPress should not take more than a minute. However, you need to keep in mind that CDN costs are significant, therefore, there should be a clear business case for using a CDN on WordPress website.