(Start of rant.) There's nothing wrong with surveying non-relational techs, or using them either (been there, many times). I just don't get the relational-database bashing that you find in articles like this. The non-scalability of relational databases is a tired strawman. Sales-pitch-styled articles like this one gloss over the technical tradeoffs in favour of making feel-good whooshy noises about alternative technologies: a huge disservice to the reader. (End of rant.)