By "tracking" I would mean the events that you can fire when a user interacts with an application, e.g. Google Analytics or other custom solutions.
Let's take search as an example. You search for "US president", you get a carousel of president card at position zero, you click on the second one instead of the first one. This can fire a tracking event. You can then process that event to update semantic relatedness between word "president" and the president entities in your KG.