You beat me into writing this =) Great article, btw! It seems to me that there are three camps of people when it comes to dbs - (1) The "I hate anything new" c

You beat me into writing this =) Great article, btw! It seems to me that there are three camps of people when it comes to dbs - (1) The "I hate anything new" camp, (2) The "I hate anything old" camp, and finally (3) The "I will pick the best tool suited to my needs" Those from camp (1) are the ones who hate anything that IS NOT relational or sql. The mongodb bashers would fall in this camp. Those from camp (2) are those who hate that IS relational or sql. The "web-scale" people would flal in this camp. Those from camp (3) are the silent majority who do their independent research, pick the right type of DB for their job, and live life happily. For my startup (Semantics3), we deal primarily with JSON strings (which have no fixed structure). We use MongoDB because a really good use case for it is to just store JSON documents with a unique id. We only run simple queries on it - basically existential (does an id exist) or count. We are aware that it's query performance is not as fast as that of a relational db. So we then index that data to ElasticSearch and run our advanced queries through that. We are really happy with our current system and it has been working great. If we had some sort of "relational" data with a fixed structure I sure has hell would have picked MySQL or PostgreSQL and used Sphinx on it for indexing. Peace.