The NoSQL movement is in direct support of the central tenet: do the simplest thing that could possibly work. Relational databases are complex beasts that have

The NoSQL movement is in direct support of the central tenet: do the simplest thing that could possibly work. Relational databases are complex beasts that have a lot more configuration and administration overhead. They are overkill for most use cases. It's not just about scale, it's about simply wanting to be able to store and retrieve values because that's what we do more than anything else. Key-value stores are simple... you put things in and get things out. Instead of calculating things on read, you calculate and store them on write. Key-value stores make a lot of things braindead simple that are otherwise fairly complex in relational databases.