Instead, the executable code sits on a remote server. That server might be owned by your corporation or government agency, and might only be a short walk from your desk. Or the server could be owned by the developer of the wordprocessor software and might be physically located hundreds, even thousands of miles away. Imagine that the wordprocessor works equally well on your Intel-based PC or your Macintosh, is always the newest version, and costs the same regardless of the operating system. The Web, while providing significant benefits, introduces new technical challenges with respect to scalability, and management of session, state, transactions and security.
Web applications can face unpredictable and potentially enormously peak loads.
This demands a high performance architecture that is extremely scalable. The Web is a stateless environment, in which the client and server are loosely coupled. Applications must keep state information from one page to another if they are to avoid requiring users to re-enter information such as user name and password from page to page. The Web presents new security issues for companies wishing to make internal databases accessible to external users. User authorization and authentication are more challenging in the Web environment because of the large number of potential users.