Memcached is a data caching system, which is used to boost the overall performance of database-powered websites by caching the calls and the responses between the visitor and the server. To put it simply, every time a given web page on such a site is opened, the script calls its database to fetch the information that should be shown to the website visitor. In case the latter clicks a link to visit a different page, the entire operation is carried out again and this generates plenty of database requests and high load on the server, particularly if the site has lots of concurrent visitors. Memcached "memorizes" this information exchange, so if any of these pages is requested again, the script no longer has to cull any data from the database, as everything is provided by the caching platform. In this way, the overall speed of your website will increase and you’ll enjoy more pleased visitors and they will be able to navigate through your site faster. Also, the Memcached platform "refreshes" its cache if any info in the database is updated, so the site visitors will never wind up seeing outdated data.