I believe that de la Vega was referring to having the ability to customize Android AT&T devices with the company's own apps, while still allowing users to download and use whatever applications they wanted onto it.

It's like if you buy a computer with Windows, it comes installed with Explorer, but that doesn't prevent you from using Firefox.

Of course, just how "open" this all would really be is up for debate. Should be interesting to see what, if any, concessions Google will press AT&T into making as far as third-party apps go.