Redis - Your advanced in-memory key-value store

Most of the NoSQL movement and buzz happened around the Map/Reduce type of storage like CouchDB and MongoDB, while Redis, mostly unknown, shines by it's simplicity. It is an in-memory database that (unlike Memcached) actually persists the data to disk to survive restarts and failures. It can help scale up write-heavy applications, but also serves as a great tool to understand how most databases work and learn to think in lower level storage terms, and can be fun to play with for small scale projects.