DorianGre writes: "I'm working on a new independent project. It involves iPhones and Android phones talking to PHP (Symfony) or Ruby/Rails. Each incoming call will be a data element POST, and I would like to simply write that into the database for later use. I'll need to be able to pull by date or by a number of key fields, as well as do trend reporting over time on the totals of a few fields. I would like to start with a NoSQL solution for scaling, and ideally it would be dead simple if possible. I've been looking at MongoDB, Couchbase, Cassandra/Hadoop and others. What do you recommend? What problems have you run into with the ones you've tried?"