It's definitely intentional. History management is more than switching from one hard reload to another, it's now used to go back to content that you had just viewed. A little more intuitive with all the javascript loading, many javascript loading pages use this to keep their site working with browser navigation.

Back isn't showing me stuff I previously viewed. It's showing me new stuff I've never seen before.

You're right, probably the nature of how they serve videos from each category. I guess history will work differently for different sites, looks here they want you to go back to a previous category, rather than the actual video.

edit: see joepestro's reply to the other post.

I think that's intentional? For me it went back to the tab I had just clicked on, and eventually back to HN. This could be by design.

"Back button being broken" is one of those usability nightmares. It's important to get it right, but on an AJAX page, what's right? Always go back to the site you came from, or go back to the previous action on your page?

I think in this case they got it wrong, but there are plenty of sites where this is correct.

In this case, changing the anchor also allows you to link to videos directly - like http://reddit.tv/#20090429-15/sports/1

Then, once on the page, you can change categories/videos without a full page reload. The anchor content controls which video you see. So I think they got it right here.

I understand the concept, but I think that they've violated the user's expectation. On most sites, tabs do not support the back button, so why should they be different? The back button is what most users will click on when there is no other obvious way to undo their previous action, but in this case there is. As such, I think the expectation of the back button is to go to the previous site, not the previous video.

Hopefully, however, they did user studies and found that I'm wrong. I, obviously, have not done any user studies, so it's easy to believe that would be the case.

This is happening for me sometimes, but it is still sometimes broken. If I try to hit "back" to go from the 2nd video I view to the first video (on plain old reddit.tv), it doesn't work. Otherwise it does. (I'm on OS X FF3)

Back-button support without page reloads is one of the most notoriously difficult features to get working cross-browser....

the content they show seems to be pretty dynamic, so changing tabs is the actual action you're taking at first, going back will take you to your previous tag, and it will load your video then. Or with the anchor getting you to the videos directly, then the history works differently, since you're actually linking to a video directly.

these features are very subtle and useful, probably and definitely not the main focus of the site ;)

when you change videos, your browser url changes to reflect that. the back button is then navigating to your previous anchor. this is the same technique used to maintain ajax states in apps like gmail.