I got a question recently from Sadek my new colleague at Eventtus about why we did decide to use MongoDB instead of something like MySQL, especially that dealing with Mongo is hard if you’re used to the use of things like Joins in other relational DBs. Luckily we had a 2 years old internal email thread where I listed why I think using Mongo would be a good idea for our case. Eventtus is 2+ years old startup, a social platform for events where you use the mobile app as a guide during events, and as a way to find interesting events happening near you. I will put the important parts of the email thread here, and sure don’t take this as a guarantee that MongoDB would work for all kinds of problems. it just was a good fit for our case, but maybe won’t be good solution for your problem and some of our future problems.
(read the rest on Eventtus’s Engineering Blog)