GNOME 3 is doing away with minimize and Maximize buttons for applications in its user interface. The basic premise being they don't make sense within the current shell design. 
Either way, it is going to be a unique experience for all GNOME 3 users.
Of course, that doesn't mean you can't minimize or maximize your applications' window in GNOME 3.
If you want the same functionality as what minimize does, then you should group your applications in different Workspaces or use the Activities overview. And if you need to Maximize your applications, you can double-click on the title bar of the application or you can use the drag-to-snap functionality.
Either way, it is going to be a unique experience for all GNOME 3 users.
