What is http Server or Web Servers?

Apache is generally recognized as the world's most popular Web server (HTTPserver). Originally designed for Unix environments, the Apache Web server has been ported to Windows and other network operating systems. The name "Apache" derives from the word "patchy" that the Apache developers used to describe early versions of their software.

The Apache Web server provides a full range of Web server features, including CGI, SSL, and virtual domains. Apache also supports plug-in modules for extensibility. Apache is free software, distributed by the Apache Software Foundation that promotes various free and open source advanced Web technologies.

A web service is an application that is run by a web server and that results in a series of URLs that will return their data in a format that is intended to be parsed by a 'generic' computer program instead of by a browser. As a result web services can use any data format they want (as long as both sides agree), but typically something like XML (specifically SOAP or so) or JSON is used.

WEB SERVER

• is a piece of software that run on a physical or virtual machine, which designed to serve web pages/web sites/web services.
• transport channel used by web server necessarily need to be HTTP protocol.
• accept HTTP requests and respond by giving HTTP responses.

WEB SERVICES

• is an application run by a web server, performing tasks and returning structured data to a calling program, rather than html for a browser.
• due to that reason, it can use any data format they wish perhaps but something like XML(especially SOAP(Service Oriented Architecture Programming)) or JSON in used.
• transport channel used by web services doesn't necessarily need to be the HTTP protocol.
• mainly there are two types of web services(in Microsoft land):WCF and asmx. WCF services are "hosted" by IIS and asmx web-services run within IIS.