The most important part for the lazy guys: So what is Redis really about? The User interface with the programmer. Redis aims to export to the programmer the right tools needed to model a wide range of problems. Sets, Lists with O(1) push operation, lrange and ltrim, server-side fast intersection between sets, are primitives that allow to model complex problems with a key value database.
As a proof try to play and download the source of our small twitter clone at http://retwis.antirez.com and imagine to write it with a plain key-value DB: it's much harder, and slower.
