various NoSQL products it's the ability to grow beyond a single server that's compelling. You make it sound as if these products scale "magically". This is def

various NoSQL products it's the ability to grow beyond a single server that's compelling. You make it sound as if these products scale "magically". This is definitely not the case. There's quite a bit of massaging needed to make riak, hbase et al scale beyond certain thresholds - and you better pay close attention to their respective peculiarities. How would you perform a query that cuts across servers and aggregates data from some of them? That's actually not very hard to implement once you understand how it needs to be done. And you do need this understanding with any k/v-store, otherwise you'll be very sad when the magic stops working (as documented time after time for MongoDB). Starting out with a known-good, mature store such as PostgreSQL can make a lot of sense when the trade-offs match your usage pattern.