When we invested in 10gen last year, the team was working on a very ambitious approach to deliver an integrated cloud platform a la Google App Engine. While they made amazing progress on that, it turned out that developer interest was focused around the MongoDB datastore. Instead of having to buy into a complete stack, most folks (at least for now) want to continue using a broad choice of technologies and combine elements as they see fit. This appears to be one of the key factors in the treme...