The Truth About Servers Page 2
For the most part, a Web server is much like a robotic dumbwaiter. The client asks it for something - a file - and the Web servers gets the file and sends it to the client. In most cases the Web server does not read or otherwise process this file, but simply hands it off to the client that asked for it.
Over the years, the "robotic" part of the Web server model has grown more sophisticated. In terms of efficiency, for example, Web servers have become more adept at handling many requests simultaneously and delivering quicker on these requests. But Web servers have also evolved to having the capability to process requests in a manner more sophisticated than simply handing over a document. As a result, Web servers have crossed the blurry line into a new territory to be marketed as "application servers" or "information servers."More information about Web servers can be found in Serving Up Web Server Basics.