The earliest supporters, those who purchased the old DATA token, got an equivalent of their original ETH investment at current prices in DTX tokens at a bonus rate of 60% to reward them for their trust in the project.
Here's an article to that effect: https://medium.com/databrokerdao/data-is-dead-long-live-dtx-and-the-release-of-the-dtx-token-sale-dates-and-terms-6cac201cbbad