This year has been an incredible one for many companies, especially technology players operating in the area of artificial intelligence (AI). They've led gains in all three indexes, from the S&P 500 and the Nasdaq to the Dow Jones Industrial Average. In fact, new Dow member Nvidia is heading for the top performance in that index this year thanks to its AI strengths.Investors have piled into AI stocks because the technology promises to be revolutionary, marking history much like the development of the teleph ...