In a recent article Tina Holmboe made something abundantly clear that a number of individuals still flatly deny - XHTML is not properly supported in browsers. While sites and Web developers are commonly using XHTML, they are typically using more of a loose HTML version and not really gaining the full power of strict XML rules. Tina also reveals that in addition to dodging browser issues, developers need to make sure they don’t serve real XHTML to devices that don't handle it well. What to do? She presents the appropriate solution - Content Negotiation.
You can read about the context of Content Negotiation for XHTML and HTML here but unfortunately she doesn't actually explain how to accomplish this practically. On Apache it is pretty straightforward: you can use mod_negotiation. However for those running IIS there was no implementation at all for this task. This is the main reason we designed pageXchanger a number of years ago; it also addresses dealing with PNG images in some browsers and not others.
What Tina proposes is to properly serve XHTML; pageXchanger is the solution for IIS. If you want to serve content dictated by device (when the device sends appropriate HTTP Accept headers), pageXchanger can do that. If you want to serve content by language it can do that too.
Unfortunately the market has yet to directly discover the decade-old power of generalized content negotiation (even though our compression products actually require this concept as well). Instead most of those who try pageXchanger seem to mainly use the product to build clean URLs, which is a bit like using a screwdriver to hammer nails – it works, but doesn’t take advantage the best features of the product.
Many search engine "experts" seem to think a clean URL is relevant to indexability and high rank. Don't get us wrong, we like clean URLs more than the next person; we wrote a paper on the very topic. The problem is that determining causality or correlation between query strings and rank is weak at best. It would appear in reality the variability and date information on the page are the more predictive factors, rather than the query string.
Very dynamic pages (regardless of query string or not) aren't going to be favored by Google or any other bot if they change too rapidly. This makes perfect sense; there’s no motivation to index an object that will change in a few moments. While the query string is one clue to non-indexable dynamism, it is certainly not the most obvious; there are a number of headers that show this regardless of URL style. Forget cleaning all tell-tale signs of dynamic pages; page changes are easily exposed by a simple double fetch by the search bot. Maybe you are doing black hat SEO content cloaking or just simply making the mistake of believing dynamic pages can be well-indexed. Regardless of the appropriateness of SEO motivations - clean your URLs anyway. That's just a good idea; even people like Tim Berners Lee think so. You know that guy -- the one who invented the Web?
That said, while we certainly aren't trying to tell people not to use pageXchanger to clean up their urls, it isn't really designed for that. You’ll get the most impact from pageXchanger using it for true content negotiation, allowing you to transparently select and serve language, image, and other content based on the user’s browser or device type. Simply put, content negotiation is a great technology for the diversity of the Web, as one page really doesn't fit all!
Cheers,
Port80