Web Services Defined
Many companies like Facebook and Twitter make their services available to users via web sites. Often these services are also available to developers to use in their apps; these are called web services. Web services are functions and content that reside on a web server that you can use via a well-defined set of rules called an API (Application Programming Interface).
The general pattern to working with web services is to formulate a request, send the request, receive the response, and then interpret the response. Objective-C comes with support for web services. To send requests and receive responses ...