Localytics uses MongoDB in production (extensively), this talk (http://www.slideshare.net/andrew311/optimizing-mongodb-lessons-learned-at-localytics http://www.

Localytics uses MongoDB in production (extensively), this talk (http://www.slideshare.net/andrew311/optimizing-mongodb-lessons-learned-at-localytics http://www.slideshare.net/andrew311/optimizing-mongodb-lesso...) is from 2011. But I sent a tweet to their CTO (@andrew311) and they are still using it ;) Cheers.