Amazon (AMZN 0.39%) has been a top artificial intelligence (AI) stock to own, even before AI was a big investing theme in the markets. The company has used AI to add efficiency to its day-to-day operations for years, by deploying robots and trying to predict consumer behavior. And it has paid off, with the company now among the most valuable businesses in the world.And it continues to invest heavily in AI. Recently, Amazon hit a milestone related to robotics, which underscores just how integral AI is to its ...