
Apparently my message http://www.alvestrand.no/pipermail/ietf-types/2006-April/001707.html has caused some discussion here and elsewhere, so I thought I should correct myself. I misspoke about 'HTTP content negotiation'. As Martin points out, content negotiation works fine for 'accept-language', and it is frequently used with 'user-agent'. It's only content negotiation based on 'accept:' that has limited applicability, mainly to cases where there are a limited number of choices. And HTTP content negotiation based on MIME types and the 'accept' header wasn't such a bad idea at the time it was introduced into HTTP, because at the time there were relatively few content-types a browser actually could be expected to support. The web at the time was mainly text and HTML. There weren't any IMG tags. (It was also one of the reasons why it wasn't such a bad idea to open a separate TCP connection for every HTTP request, because 'a web page' could be retrieved with a single request.) It was only the introduction of using separate HTTP requests for embedded images (rather than a compound document format), and the explosion of image types and other kinds of embedded content that made using Accept: with a list of content types impractical for the 'web browsing' case (and also required some changes to HTTP for persistent connections.) Larry -- http://larry.masinter.net