Finally I see a lot of small sites, forums, blogs, that can't scale easily to small numbers using relational DBs. When MySQL was in growth stage, about 50% of

Finally I see a lot of small sites, forums, blogs, that can't scale easily to small numbers using relational DBs. When MySQL was in growth stage, about 50% of the downloads accounted for users who were downloading a database for the first time in their lives! (got that piece of info from early MySQL folks). If a small site, forum, or blog can't scale easily on a relational database it is because the developer doesn't know what they're doing. You can make an argument that relational solutions aren't user friendly because they have defaults not suited for small, high-performance sites, or too many features that cripple performance if not used correctly, but IMO that's a silly argument. People don't blame a programming language because their program is slow since they used a O(2^N) algorithm where O(N log N) suffices. Why do people blame a DBMS when they write nonsensical queries that couldn't possibly evaluate in real-time merely for giving them an option to write such queries? Also it's not just a matter of scalability: latency is a very important constraint. Many relational databases have sophisticated schedulers that reorder events to maximize queries per second, unless an event has been in the pipe for too long, in which case it is given higher priority and pushed through faster. Most NoSQL products do not even begin to approach this level of sophistication. Even MySQL gives excellent latency characteristics if you know what you're doing - just ask the Facebook folks, they're very serious about latency. Good latency performance is certainly not restricted to NoSQL stores. Most SQL vs. NoSQL debates usually have the same resolution: traditional DBMSes let you shoot yourself in the foot, while NoSQL solutions usually don't. With a traditional DBMS you better know what you're doing, while with a NoSQL solution you can usually get away with just jumping into it. Nine times out of ten, that's the value proposition. Most of the time it isn't performance, latency, a better/different data model, or anything of the sort.