Memcached is a memory caching system, which is used to boost the speed of database-powered sites by caching the requests and the replies between the user and the server. In simple terms, every time a specific web page on such a site is requested, the script sends a query to its database to get the info that should be shown to the visitor. In case the latter clicks on a link to go to some other web page, the entire procedure is performed again and this results in lots of database queries and higher server load, especially if the website has a lot of simultaneous visitors. Memcached "remembers" this exchange of information, so if any of these pages is requested again, the script no longer has to pull any data from the database, since everything is delivered by the Memcached platform. In this way, the overall speed of your website will increase and you will enjoy more satisfied visitors and they’ll be able to navigate through your website much faster. Additionally, the Memcached platform "refreshes" its cache whenever any info in the database is changed, so the website visitors will never end up seeing old content.