The number of users with the latest patch on Opera and Firefox never exceeded 46% and 80% respectively. (80% seems pretty damn good to me, but does leave an awful lot of people exposed.) Interestingly, Internet Explorer couldn't be used for this study because the browser string doesn't reveal the patch level. You could argue that this was for security reasons, or you could argue that Microsoft don't really want people measuring their version demographics.
An interesting idea – the answer is "no", of course, but it's great to see different kinds of databases emerge for different use cases. The databases behind the scenes in web apps are typically relational, despite the concept of relational databases not being designed for application back-ends. Could there be a better model for this specific use? Probably.