In the early days of Systinet (summer of 2000) I made the following proposition that served as a guiding principle for the company development: The web will be full of services within the next five years.
We saw the massive growth of services on the web since then. From Flickr to YouTube, from Gmail to Twitter and thousands of others. And the circle has closed a few days ago when Google announced their service platform: Google App Engine. It’s the ultimate service container as it only supports creation of web services:
* An application can only access other computers on the Internet through the provided URL fetch and email services and APIs. Other computers can only connect to the application by making HTTP (or HTTPS) requests on the standard ports.
* An application cannot write to the file system. An app can read files, but only files uploaded with the application code. The app must use the App Engine datastore for all data that persists between requests.
* Application code only runs in response to a web request, and must return response data within a few seconds. A request handler cannot spawn a sub-process or execute code after the response has been sent.