When somebody asks us to create a web application, the software requirements will be Apache, Mysql, PhP(LAMP where L stands for Linux). Imagine an application which stores data in main memory instead of disk, this will increase your application performance tremendously. One such application is Redis. Redis stores data on memory instead of disk and will periodically sync with the disks(if necessary). Why Redis?: Redis will be faster as it keeps data on memory. I read somewhere Memory is like disk and disk is like tape for redis. Redis allows lot of data structures. Basically its a NOSQL database( http://en.wikipedia.org/wiki/NoSQL ) . They dont support table or database schema we use traditionally. For them everything is key value pair as in hashmap. Redis allows a key to have values of types- string, set, sorted set, list, hashmap. To understand each data structure and the command they support, have a look at http://simonwillison.net/static/2010/redis-tutorial/ Lot of ...