Starting with SharePoint 2013, we are beginning to go down the path of reducing our reliance on Alternate Access Mappings, or AAM. It is still available, but our suggestion is that you try and model your farm designs first as a single web application and then use host header site collections in it. This is the model that we’ve put a lot of energy into making “just work”, because it is the same model that we use in Office 365. We’ve also added new features for host header site collections in this release so you can functional parity with alternate access mappings. One of the big things we did is to allow you to associate multiple Urls with the same site collection. This only works for host header sites, but as you can see from the PowerShell here, we’ve added commands that let you use multiple Urls with a site, the same way in which you would create multiple Urls with zones when using AAM. We still support zones as well, so for the same reasons you might have used zones previously – like you wanted to configure different authentication methods for a site – you can use that same approach with host header sites in SharePoint 2013.