CDN, Content Delivery Network or Content Distribution Network.

Using a CDN will gain you a nice chunk of SEO score with Yslow vastly increases your page loading speed and increased security with a shared SSL. For my website, I am using Cloudflare what offers free services with an option to buy a subscription every month. A CDN will store the content of your website over a cloud network of data centres and then serve the content to the end-user from the closest data centre. You will have to create an account with Cloudflare to use their services, but the basic plan will be free if you have more websites you can add them as well but make sure to update your DNS settings for each domain. Important to remember that the SSL certificate will take up to 24 hours to be issued to your site do not enable HTTPS links in Joomla and the .htaccess file. If you already own an SSL certificate you can also use that throughout the Cloudflare CDN service make sure to check your settings. The process of adding your website to the Cloudflare service is a click by click process the only real effort is pointing the name server to those of CloudFlare in your domain registrar. Two name servers will be displayed that you need to add in your domain DNS registrar, most likely your host provider has examples for most hosting company's. Cloud Flare also expanded their support and has various examples on how to update your DNS.

1. Enable DNS Settings in Cloud Flare in DNS Settings.
2. Enable SSL and wait for 24 hours and select the Flexible option. Unless you have an SSL certificate with your hosting, then you will need to enable Full setting.
3. Enable Speed, Caching and Network settings as you desire. These will be site-specific, but Auto Minify, Brotli, Caching Level Standard, and Always Online TM are reliable options to use.