Google announced last night that you can now, or in the upcoming weeks as Google rolls it out, customize and rearrange the order of the products and apps within the Google navigation bar as you like.
Meaning, if you want to move up the Google Maps icon and move down the Google Sites icon in that navigation bar, you can by dragging and dropping the icons where you want them.
Here is an animated GIF of it in action:
If you do not see this yet, do not worry, Google says they are “rolling this out over the next couple weeks, so please hold tight if you aren’t seeing it yet.”