It sounds neat, but how come I don see content negotiation used online?
Good question. First, there are few tools to do it. On Apache, you do have modules such as mod_negotiate, but even there things are tricky. Secondly, many developers just don’t know about it. There are a few sites using a version of the technology currently, though they have developed a custom in-house solution. For example, The World Wide Web Consortium (W3C) site relies on the ideas PageXchanger uses quite extensively and many specifications such as RFC2295 have been written concerning this technology.
