[ajross]

This is my intuition too. The iPhone model is a single app page swimming in a top-level sea with others. For some things, that's fine. But for many apps (browsers are obvious, but also games that have splash menus, anything with a folder-like hierarchy, etc...) there is a clear and obvious "back" metaphor. And iOS just doesn't do back.

That's not an excuse for Android apps that use it inconsistently obviously (though the framework is pretty good about making sure obvious implementations do the obvious thing). But on the whole I think it's a very good feature.

Likewise, "menu" is something that almost everything has and probably deserves a hardware button (or at least a button with a persistent location and presentation -- the Galaxy Nexus apparently has no "hardware" buttons outside the touchscreen).

The "search" button that so many Android phone have, on the other hand, is completely beyond me. Ridiculous.

[Zhenya]

Search button at first seemed superfluous to me also, however I have really found a few great uses. I use it all the time now:

Instead of launching the browser and then going to an web address, I can punch it in after hitting the search button. Opens browser with that address.

I never have to launch the browser and then search for something.

It's also great if you need to find someone in your contact list and dont feel like scrolling

The search button is also contextual, so that if you're within an app you can search for whatever(maps, sms etc)

Also long pressing on the search button brings up the voice commands.

[ajross]

Sure, but I don't think that's the right criteria. Any task can be made faster by associating a fixed button with it. But every fixed button has a cost. If you do a ton of "searching" then sure, this is good. My personal usage would be improved with a "go directly to email" button. Most people don't search that much. Or if they do, they do it from a desktop widget (even faster IMHO). I don't think it's an appropriate usage for the very precious physical space on the front panel.

[Zhenya]

Interesting point about the desktop widget. Initially, i believe in 1.0 and 1.5, you could click in the widget and type.

After that the widget was updated to launch the search app just like the search button. It basically became a 4 column wide search link.