This question is a little more general than the title implies. I haven't been exposed to almost any server related code, so I hope you can be gentle with your replies.
What I want to know, really, is what kind of server I want, or need for a particular task. Here is the hypothetical task: I have an iPhone app, everybody on the app participates in a bunch of "text message" like conversations. So I can look at all the different conversations going on, and add my comments to any conversation. The conversations will also be broken down by category.
What is the appropriate way to both store, and retrieve this information (and update, etc)? Will I need an EC2 server in conjunction with S3 storage? Should I even bother with the cloud? Essentially, how would I access this information?
Sorry for such basic questions, I am learning as I go here. Any point in the right direction, even if it's not an answer, would be greatly appreciated.