On a touch device, side-scrolling feels very natural. The problem is that Apple is trying to create a consistent set of rules for devices that are inconsistent (with very good reasons) in their UI designs. A touchpad is not the same as a touchscreen.
I'm OK with either vertical or horizontal scrolling -- but not both at the same time. Everyone in my company has a minimum of a 1920x1080 screen, and most have more than one or something even larger. We should not have to scroll in more than one direction, and a layout that makes that happen is ugly.
(I also agree that mapping forward/backward to the horizontal scroll is worse than ugly: it breaks user expectations by being inconsistent.)
I'm a big fan of sideways scrolling in the right places. Apples own product nav on the website would be a great place for two fingered sideways scrolling to be implemented.
It didn't work with swipe gestures as I recall. I remember because I was looking for a good side-scrolling implementation that used swiping about 2 years ago and thought that might have it.
Horizontal scrolling is a pain in the rear and I hope most web developers stay away from it entirely. I can't think of any good reason any web page should ever scroll unless your monitor is smaller then 1024px.
> I can't think of any good reason any web page should ever scroll…
They give you a very good reason why the webpage should horizontally scroll: task boards. I've implemented and used task boards before and hit this exact same issue.
Horizontal scrolling is only really an issue for those users who don't have a decent device for horizontal scrolling. On trackpads and the Magic/Mighty mouses, horizontal scrolling is very natural.
Anytime I have to scroll horizontally in a browser, it feels awkward and non-standard (especially if I have to scroll horizontal AND vertical).
Whilst it's just my preference, I'd sooner not have any web pages scroll horizontally.