In this post we will discuss about Web Front End Server (WFE) in SharePoint 2010. Also check out some articles on:
A web server handles the web page request from users and process the request and returns the data. In a SharePoint farm, there can be multiple web front end (WFE) servers and have a Network load balancer which will be responsible to distribute the request between the front web servers.
But as the number of users grows you can add more WFE servers. Check one fig below: