I can't help but get the feeling that within a few months they'll be running back to Oracle or some other real database system.
At this point, anyone who works with databases in industry knows that "NoSQL" has come to mean inconsistent data, corrupted data, and silently lost data.
One just can't throw away atomicity, consistency, isolation and durability without running into some serious problems.
And that's totally ignoring how it becomes damn near impossible effectively query NoSQL databases. Sorry, writing complex queries in some imperative subset of JavaScript is totally the wrong way of doing things. Intentionally not learning SQL takes more effort than learning how to use it!
I was hoping to learn why/how they might be doing this somewhere in this thread, because their implementation seems to be the exact thing that you want a relational database for, and not where NoSQL shines. I also don't see what implementation they used since NoSQL is pretty non-descriptive, and at this point seems to basically mean that they aren't using Oracle, DB2, MySQL, Postgres, or MSSQL.