A major activist investor just took a stake in the coffee giant. Could positive changes be on the way?Notable activist investor Elliott Investment Management recently took a substantial position in Starbucks (SBUX 1.00%), according to a Wall Street Journal report. This isn't surprising, as the coffee giant has actually produced negative investor returns over the past five years despite posting strong growth in the business. In this video, Fool.com contributors Matt Frankel and Lou Whiteman give their takes ...