I have been tidying up, both my mind and mailboxes. Last month I was looking at a database technology selection problem and was indirectly pointed at “A visual guide to NoSQL”, or at least the picture. I have updated my wiki page on NoSQL, to include the reference and the image. The massive number of post relational systems available today reminded me of Stonebreaker’s article, The End of an Architectural Era (It’s Time for a Complete Rewrite), in which he first suggested that the monolithic poly-functional database’s day was over. Alternatively you can access it and some of his subsequent work here, at highscalability.com.