What's in an AVA?

In 1980, the US approved its first American Viticultural Area (AVA), in Missouri. Since then 260 AVAs in 34 states have been added, an average of just over six a year. California has more than half at 143, Oregon has 22 (four are shared between states), Washington has 19 (four shared), and so on. It’s getting to the point that when a new AVA is announced and I start getting press releases, I, perhaps like you, am left wondering, ‘does this matter?’...