We're trying to decide what architecture to use for an upcoming web application that will eventually have a mobile portion as well. The core of the project is a social networking web application, and the mobile portion will most likely have a limited subset of the web functionality.
The two options we are looking at is either a complete web service back end, or using a traditional MVC framework for the web application and then developing web services on the side for the mobile application later.
I'm not feeling good about the idea of using web services only because it doesn't make sense to me, but I am having trouble clarifying my issues with it.
So what should I consider when trying to determine if we should use a complete web-service backend for our project instead of traditional MVC with web services only available when needed for the mobile portion of the app?
I'm looking for a comprehensive answer to this question, not many answers each containing one piece of the answer.