The newly concieved XML technology seemed to provide a solution. Had webmasters adopted XML as the publishing format of choice, there would be no need to have multiple sites. You just provide a separate XSL template for every different browser or device in which you want to control the appearance of your information.
This was not happening, though. XML has since become extremely popular and useful for different purposes. But it has not become the language of everyday web publishing. Not even XHTML, which is an XML-ization of HTML, has been widely adopted. Rather, XML is the default format for the communication of structured data - everywhere except in web pages!
Next... Fifth generation and beyond