A content delivery network system is a collection of internet servers which serves about one third of the most visited websites. The system improves speed of access for download-able data, applications, queries, web objects and media streams, as it increases the access bandwidth and reduces latency.
It contains copies of data located at different nodes of the selected servers, providing service from servers which are located geographically close to the user, hence saving access time. Furthermore, this unique method assists in reducing load on web application and improves scalability. There are several types of Content Deliver Networks which includes third party CDN providers too.
Akamai is one of the most famous CDNs which support many of the Fortune 50 sites. Akamai delivers between 15-30% of all Web traffic. Though Akamai is the leader, if your work is restricted to the US, there is no need to spend on Akamai as you can go for other efficient but cheap alternatives, such as the ones mentioned in this list.
Some companies may prefer to roll their own CDN using open source libraries along with freely available public CDNs just like for jQuery and other popular libraries.
Here is a list of 15 popular CDN alternatives to Akamai–