Initially, I believed that the hash hack was a necessity, but after observing the recent updates from Facebook, my perspective has shifted.
The original hash hack (not certain if this is the correct term) involved changing location.hash to save a state in the URL without refreshing the page. This technique was commonly used by Google's apps, Facebook, and more recently #NewTwitter. However, I noticed today that Facebook no longer includes the "#" symbol when using a "modern" browser like Chrome or Firefox. Through developer tools and Firebug, it was confirmed that they are not reloading the page.
After conducting a brief search on Stack Overflow, the closest solution suggested Flash, but even after disabling Flash, Facebook continued to function smoothly. The possibility of HTML5-era APIs being related to the changes in Chrome 8 dev and Firefox 4 beta crossed my mind, but the complexity of Facebook's code prevents me from debugging to uncover what alterations they made.
As this is my first question here, I'm hopeful that someone may have already found a resolution to this issue.
Thank you all.
P.S. Not operational on IE8; yet to test on IE9 beta.