I was wondering about this too. I have a database-heavy, performance-sensitive app in mind. It will serve approximately the same logic over both a raw UDP socket and an HTML5 app generating its pages on the fly. I know that sounds odd but some users still have ordinary phones on cheap data contracts. Interactions between all these people are initiated by one of them, whereupon I need to haul their data out of the DB, process it as some kind of state-machine in a thread set up for the interaction, and then log the gossip to the DB afterwards. I'll probably use postgres if nothing speaks against it cos it'll be a linux server and mysql is considered buggier and slower under load.