What are two methods being developed to track consumers across devices?

Two methods being developed to track consumers across devices are deterministic cross-device tracking and probabilistic cross-device tracking. Deterministic cross-device tracking relies on personally identifiable information such as e-mail address used to log into an app and website on different devices. Facebook, Google, Apple, Twitter, and other companies that have very large user bases and have both desktop and mobile properties that require logins are the most likely to be able to effectively exploit deterministic matching. Probabilistic cross-device tracking uses algorithms developed by vendors such as Drawbridge, BlueCava, and Tapad to analyze thousands of anonymous data points, such as device type, operating system, and IP address, to create a possible match. This type of matching is less accurate than deterministic matching.

Makes sense