A good site is also a fast site. In the neverending quest to make my site faster, I came up to the CDN idea.
Wikipedia tells us more about it:
A content delivery network or content distribution network (CDN) is a system of computers containing copies of data placed at various nodes of a network. When properly designed and implemented, a CDN can improve access to the data it caches by increasing access bandwidth and redundancy and reducing access latency. Data content types often cached in CDNs include web objects, downloadable objects (media files, software, documents), applications, live streaming media, and database queries.
Simple exemple. Your server is in America, a visitor in Belgium. Normally, the data will have to travel all the way from America to Belgium. With a CDN, the data will only have to travel from a coutry in Europe (France maybe) to Belgium. this makes a great difference when it comes to speed.
In my case, it made my site 3 to 4 times faster !
How to setup the best free CDN?
1- go to https://www.speedymirror.com/register.php and register a free account. afterwards log in.
2- go to https://www.speedymirror.com/mirrors.php and add a new mirror.
3- when the mirror is finished, download and install the W3 total cache plugin (http://wordpress.org/extend/plugins/w3-total-cache/)
4- Create a new cname at your hosting (cpanel)
5- configure it in the W3 total cache plugin and wait a couple of time
6- you can check the working at https://www.speedymirror.com/stats.php
I hope you have the same results as I have. Do not hesitate to post it in a comment 
