[siglesias]

Not every app needs a back button, though. It's really that simple. That and the behavior is unpredictable because the button can't be labeled, being hardware. If a modal dialog pops up, say in a game, it will be a gamble whether the back button dismisses the dialog or shoots me back to the task I was doing prior to firing up the game. It's not that well thought out an idea.

Now, placement is a different issue and we can argue why these designers chose to put them where they put them. But it has nothing to do with the button being hardware versus software.

[king_jester]

By default in Android, back key pressed when dialogs are showing simply dismiss those dialogs. There are app authors who override back button behavior (wrongly) and break this paradigm. The persistent availability of the back button is great, for the most part, as I know I should be able to get back to where I was in most scenarios.

[gfodor]

My post was entirely about placement and now the new iPhone's screen size goes against the convention of top left for back button on iOS. The fact that so many people are reading deeply into my mention of Android and jumping in to talk about hardware back buttons and/or defend Android is bizarre to me.