I've been using MongoDB to rewrite the activity feed on one of my apps. I wouldn't use it for everything though (not just yet anyway). Having said that, the gu

I've been using MongoDB to rewrite the activity feed on one of my apps. I wouldn't use it for everything though (not just yet anyway). Having said that, the guys behind Harmony (http://get.harmonyapp.com/ http://get.harmonyapp.com/) use MongoDB for everything, as far as I know: http://railstips.org/blog/archives/2009/12/18/why-i-think-mongo-is-to-databases-what-rails-was-to-frameworks/ http://railstips.org/blog/archives/2009/12/18/why-i-think-mo...