Here, I described about benefit of XML language. Corporates are increasingly moving from the classic Client/Server two-tier application models to the three-tier model. The browser acts as a front end, and interacts with a middle-tier web server, which in turn communicates with a back-end database server for storage. This three-tier architecture has several benefits over two-tier architecture, including easier scalability and better security. XML will make possible richer implementation of such models through structured data exchanged over HTTP. The benefits of XML can be classified into the following: 1) Bussiness benefits of XML 2) Technological benefits of XML 1) Business benefits of XML The various business benefits of XML are as follows: • Information Sharing The XML can be used facilitate business. It is one of the greatest benefits of XML. XML allows businesses to define data formats in XML, and easily build tools that read data, write data and transform data between XML and other formats. This has allowed a number of businesses and industry consortiums to build standard XML data formats. Areas such as Electronic Data Interchange (EDI), inter-bank payments, supply-chain, trading and document management are all the subjects of ongoing XML-based standardization undertaken by industry consortiums. The ability to link enterprise applications is a key focus for many companies, and has produced cost savings and increased revenue for many enterprise customers. In particular, many businesses aim to improve Customer Relationship Management (CRM) by creating a single logical view of each customer across multiple existing systems. XML is an important technology to create this single customer view. Furthermore, because XML makes it easy to relate structure to content, XML subsets can be defined with specific industries, or applications in mind. For example, XML has been used to define standard data formats for the banking industry. In the same manner, a standard could be developed specifically for flight booking systems, thereby allowing airlines to easily exchange information. • Single application usage The business benefits of using XML within a single application are less compelling, but they are very easy to achieve, and so we have a number of applications that use XML internally. XML is a very powerful and flexible language for describing the complexities of the real world. Since XML can describe complex data, it means that it can be a powerful tool for creating new applications. The extensibility of XML means that the application can grow and develop without major changes. XML allows businesses to define data formats in XML, and easily build tools that read data, write data and transform data between XML and other formats. • Content Delivery XML has a number of key benefits for content delivery. The main benefits are the ability to support different users and channels, and to build more efficient applications. Channels are information delivery mechanisms, for example, Digital TV, Phone , the Web, and multimedia kiosks. Supporting different channels is an important step in delivering e-business applications to customers through their chosen medium. XML is a key technology for this. For example, a customer and a supplier both need to access the same on -line product catalogue. Although the information is the same, the visual emphasis will differ, depending on who the user is. The customer will be more interested in looking for information on functionality, pricing, and availability, while the supplier will want to have easy access to catalogue maintenance and inventory information. All this information might be stored in a single XML document and be displayed differently by the application. Using XML for content delivery has been limited by the non-availability of XML-enabled browsers. 2) Technological benefits of XML The Technological benefits of XML are as follows: • Re-use of data The librarian could re-use the publisher’s data, because it is in a common format, and we could also re-use the data when we built our meta-catalogue. Of course there are many common file formats in the world of computing that have allowed data re-use. There have usually been proprietary and application specific. XML is neither application specific nor proprietary. • Separation of data and presentation If we compare five years old Web sites, with the ones at present, they have changed a lot. Any successful Web site will probably have at least one redesign a year. That is not simply to cater to latest trends. Successful Web sites analyse and react to feedback from users, and redesign the site to be more productive and intuitive. Let us return to the example of the library Web site. This Web site is also redesigned, but the underlying data remains in place. So it makes sense to separate the data output from the Web site design. There is still another, even more compelling reason to separate data and display, which is the rise of pervasive computing. Pervasive computing takes place when computing devices become integrated into common everyday appliances, for example, mobiles, televisions, printers, and palm computers. Each of these appliances may have a different display technology, and require different instructions on how to display the data. The same search of the library catalogue should be viewed on a mobile phone or a high-resolution PC. This can be achieved by using XML. • Extensibility HTML has been a constantly evolving standard since it emerged. One of the problems it has faced, is that companies wishing to go beyond HTML, have often extended it. Browser suppliers regularly add non-standard extensions to HTML. Similarly web server manufacturers build “Server-side” extensions to HTML. These include Microsoft’s Active Server Pages, Java Server Pages, and many others. This has led to many confusing variants of the HTML standard, causing difficulties for Web developers, tools vendors, and ultimately for end-users. As the name implies, extensible Markup Language was designed from the beginning to allow extensions. If we go back to our example of the library, when the books were first indexed, the Web did not exist. Probably the library catalog has no references to Web sites in it. Nowadays, many books have a companion Web Site, and the librarian may wish to reference it. If XML were used to develop the catalog, then this could easily be accomplished. Importantly, with XML, old software is not disrupted by the addition of new information. • Semantic Information The final major benefit of XML is that it builds semantic information into the document. Semantic information (or meaning) is what allows readers to decide whether the book is about the color brown, or written by Brown. An HTML-based Web search engine cannot do that, because it cannot distinguish between the title and author in the document, there isn’t enough semantic information in the HTML page. With XML, the document includes self-descriptive terms that make it possible to know what the meaning of the document,is. • Other benefits The other benefits of XML are, that it is human-readable, tree-based, and is easy to write program. As time goes on, a large number of XML tools will emerging from both existing and new software vendors. It is human-readable, because it is based on text and simple customised tags. The tree-based structure of XML is much more powerful than fixed-length data formats. Because objects are tree structures as well, XML is ideally suited to working with object-oriented programming. In particular, many people believe that there is an excellent affinity between Java and XML. Lastly, XML is easy to program, because there are already standards for XML parsers. XML parsers are the subsystems that read XML, and allow programmer to work with XML.