This article is weird: Bing has not ditched its zoom slider, it has merely obfuscated it, hiding it behind a pair of (still present) looking glasses. In fact the author even mentions that in the linked article:
> In a way, though, the old slider is still there: all you have to do is hover over the new zoom controls (the magnifying glass buttons), and a new slider appears. From there, you can use the new slider in the same way that you would use the old one.
Now there really are two broad cases, zoom-slider wise:
1. On many mobile devices, pinch and unpinch are becoming pretty standard "zoom" and "unzoom" commands. Since they're analog and when they're handled correctly by the OS, they make sliders redundant as a control device. On the other hand, sliders still have one great advantage: they show the range of motion available and the position of the current view within that range
2. On non-mobile devices, you can not even be sure the device has a hardware way to manage zooming, and even when it does that devices may not be analog or accessible. Or it might be used for something else already (mousewheel to zoom on the map in a web page? How about no?)
also, taking common UI patterns on mobile devices and using their popularity as an argument for using those patterns on the web seems invalid to me. Sure, it works on mobile - but users have a different expectation of how things work on mobile.
I both agree and disagree: new usage patterns on mobile should be studied and considered to see whether they can be adopted on desktop/non-mobile devices. For instance applications which keep their state permanently saved are pretty much mandatory on modern mobile devices, but very rare on desktop (Notational Velocity is one of the few apps I know which does that), yet not having to save ever would be a pretty nifty desktop UI pattern.
On the other hand, mobile UI patterns don't necessarily translate well indeed. There will probably be a lot of chaff, just as for a long time mobile UI suffered because developers were using desktop UI patterns on mobile devices which have not the wrong resolutions (nb: modern mobile devices have far higher resolutions than desktop machines 15 years ago) but the wrong input and output (physical size, shape, rest position, …).
> In a way, though, the old slider is still there: all you have to do is hover over the new zoom controls (the magnifying glass buttons), and a new slider appears. From there, you can use the new slider in the same way that you would use the old one.
Now there really are two broad cases, zoom-slider wise:
1. On many mobile devices, pinch and unpinch are becoming pretty standard "zoom" and "unzoom" commands. Since they're analog and when they're handled correctly by the OS, they make sliders redundant as a control device. On the other hand, sliders still have one great advantage: they show the range of motion available and the position of the current view within that range
2. On non-mobile devices, you can not even be sure the device has a hardware way to manage zooming, and even when it does that devices may not be analog or accessible. Or it might be used for something else already (mousewheel to zoom on the map in a web page? How about no?)