So, where is the solution that gives you pretty urls with HTML5 history for those who can have it, and identical urls preceeded with hashes for those who can't, in an easy-to-use plugin? Also, where is the framework/pattern that makes both styles of URL work in the absence of either technology using something like mod_rewrite?
In other words, how do we get it all, future-proofed, without so much frustration and so many debates?
That's a nasty solution though, because then every item on your site ends up with two URLs - a concrete, proper, doesn't-break-the-web one and a lousy Ajax hashbang one.
Having one URL per piece of content is especially important in this age of sharing and aggregation, where you don't want your pagerank / number-of-shares / other metrics spread equally across two different URLs.
And for my current site, those concerns are big. Sharing content is a key focus. The design has as a core philosophy: one simple, highly-readable URL per piece of content.
And that is exactly what I've done on my most recent site. I see this as the best solution, since the site caters to people who are more likely to have modern browsers that support the History API, giving them rich interactions and leaving only a slim margin of viewers with a "static" version of the site.
But it would be nice to be able to degrade nicely, and still support some degree of ajax with linkable states. Beggars can't always be so choosey, I suppose.
In other words, how do we get it all, future-proofed, without so much frustration and so many debates?