One property of these charts is that the data is normalized so that the 'winner' takes up 100% of the width for any given time-sample. This is useful if you're

One property of these charts is that the data is normalized so that the 'winner' takes up 100% of the width for any given time-sample. This is useful if you're trying to imply that the data is zero-sum, but not useful if you're interested in understanding the changes for any one participant relative to itself, or two participants relative to each other. I think in the example, Apple's growth would be far more dramatic on a simple line chart.