I'm confused - I thought they were trying to get devs to standardize that, and that they also changed things in ICS? The way it currently is (for me on Gingerb

I'm confused - I thought they were trying to get devs to standardize that, and that they also changed things in ICS? The way it currently is (for me on Gingerbread) that some apps have the back button go back to the previous view, but some go to the homescreen. And if I (say) open a browser link in an app, the back button will take me back to the application. (That may also be app-specific, but I just tried it out with one app). So what's different on the Nexus, and what part of that is ICS-specific changes (as opposed to things that app developers have to implement independently)? (Apologies for the confusion, but I still haven't seen an ICS device, and I don't develop for Android, so my knowledge of this is fairly passive, as a consumer).