First generation web sites are built of static web pages, pages which are more or less simple text files. Static pages must be changed manually and updated on the web server. For a web site consisting of a small number of pages with information that seldom changes this approach is acceptable. The overhead of managing static sites, as well as the possibility for editing mistakes increases exponentially as a web site grows. Dynamic web sites, where pages are generated by a server each time they are requested by a browser, have many advantages over static sites.
Dynamic sites are responsive to users.
They can be customized to a particular client and even be designed to 'remember' a client's set of preferences, order history, billing information, etc. Any element of a dynamic site becomes programmable. This not only includes information displayed on the site but also look and feel characteristics, such as layout, colors, etc. Sweeping changes can be made to a web site with a very small change in the source code. Dynamic sites take advantage of the latest developments in object oriented design.