<a href="http://www.usabilityviews.com/ajaxsucks.html" author="Jakob Nielson">Why Ajax Sucks (Most of the Time)</a> is a critique of Ajax that borrows almost all of its text from a critique of HTML frames made several years ago. The author claims the article is a spoof, but, given that the complaints made about frames were valid at the time --- and still are --- and that the complaints are just as valid for the current batch of web applications, it's hard to see what's so funny about this "spoof". There are those who argue that frames in fact have not died out, since they are used on almost every web site to house advertising or as invisible containers for dynamic content. That argument misses the point of the initial critique, which derides the use of frames for <i>navigational</i> purposes. Sites using frames for navigation have gone the way of the dodo --- for exactly all of the reasons mentioned all those years ago. <h>A concrete example: Gmail</h> I'm an Opera user and I have mouse gesturing hard-wired into my brain. I sweep the mouse from right to left without even thinking about it. I expect to go back to the previous page in an instant, as Opera also provides the convenience of using its cache to serve up recent page --- unlike Firefox and IE, which still see the need to go online to check whether the page <i>I was just at one second ago</i> needs to be updated. When I take this --- admittedly spoiled --- behavior to an Ajax-enabled site like Google Mail, I'm crippled. I frequently sit in front of an empty page because, as mentioned in the article above, <i>back simply does not work</i>. Sweeping the mouse desperately from left to right (to go forward again) brings more white pages, with a small <iq>Loading...</iq> hint in the top left of the page. A glance at the bottom of the page shows no Opera progress bar, which means Google is not loading anything. The only tool I have left? Reload. The Google Mail page weighs in at over 300KB (Opera's progress bar also conveniently shows how much page it's loading), so that's no small chore. If you've managed to go back too much, you might have logged yourself out, in which case you get to completely start over. It is, indeed, a usability catastrophe. The ideas in the UI are interesting, in that everything happens inside one window, with more and more data loading into the view without replacing the old data. It's just impossible to navigate.