Do not worry. HTML will exist together with XML. XML is much more powerful and actually it can be easier then HTML and so more and more people will shift to XML, but browsers will still understand both.
XML (+ RDF + several other standards) is more then formatting language. My prediction is that they will have as huge impact on our lives as the steam engine had, becouse they will enable to very effectively share, use and leverage informations.
The simplest definition of XML I have seen is that XML is to data what HTML was to text. Because one is now dealing with data, not text, it has to be precise. HTML could always cope with ambiguities, because it was being parsed as text by people. Arguably, when it comes to chemical data, accuracy then becomes essential, and the ambiguities of HTML are no longer acceptable (something which hardened information specialists in chemistry have known for years, and which caused them to scoff at the Web and HTML when it came out in 1989-1993!) I might also add that whilst HTML and XML could be served out by simple "web servers", the real strength in XML is in deploying it in so called "XML repositories", which at one level can be considered as highly integrated queryable document, data and software servers To understand the enormous power of XML, take a look at http://www.upyp.com/ which is an XML-based catalog (wrapped with HTML probably via an XSL stylesheet so that existing browsers can process it). To quote a Netscape/AOL employee (AOL are major players in e-commerce) about the above site " they solved the headache of business-to-business catalog interoperability, allowing automatic server-to-server catlaog exchange, all in XML, and it is working now! Unlike most other competitors claiming XML compliance but are mostly hype. It is to my amazement that they solved the problem in such a straight-forward way that everybody can easily accept and hook their catalogs into it. This is an Aha solution to me." E-commerce is likely to be the most immediate application of XML (in the above catalog for example, note how the prices can be styled for your local currency, using automatic unit conversions) the scientific and chemical implications are enormous. We have an interesting XML chemical repository nearing completion, and when its ready for the world to test, I will announce it via this forum. It reminds me of the heady days of around October 1993, when NCSA started maintaining a global index of web sites. About one a day would be added, and you could easily keep track of them all! By about April 1994, NCSA had stopped trying to keep up. From the point of view of XML, were are at about November 1993!! Dr Henry Rzepa, Dept. Chemistry, Imperial College, LONDON SW7 2AY; mailto:rzepa@ic.ac.uk; Tel (44) 171 594 5774; Fax: (44) 171 594 5804. URL: http://www.ch.ic.ac.uk/rzepa/ chemweb: A list for Chemical Applications of the Internet. To post to list: mailto:chemweb@ic.ac.uk Archived as: http://www.lists.ic.ac.uk/hypermail/chemweb/ To (un)subscribe, mailto:majordomo@ic.ac.uk the following message; (un)subscribe chemweb List coordinator, Henry Rzepa (mailto:rzepa@ic.ac.uk)