@rootKID
Its just a daemon running on your server - it uses ram to store data, so we use it any where a static sql query would normally hit the the database for every user on every single refresh, so what does it do next ?? Well simply uses ram to store say the data we requested from that sql query so one hit gets the query values then every other hit after that is served from cache, so its an obvious observation that in turn free's up major mysql resource on the tracker due to all you main hard hitting querys in use all over the source code using memcache : ) Memcached is another method and is more efficient because you can use multiget and other functions not available on memcache but thats no important to you.