Caching means temporary storing area for data. When we cache a data, the second request to fetch the data will not reach the server; it will fetch the data from the cache itself saving the time, network and the additional traffic. WCS provides a good support for dynamic caching. To know kore about the same, check the following link.
http://wcs-tips.blogspot.in/p/blog-page_23.html
http://wcs-tips.blogspot.in/p/blog-page_23.html