If this property has been added to an object, and then an AIWatchObj link is then made to the object (in that order), the link Data will get its values from the property.
To explain by example, if a TrolPausePt is created, and an AI is then given an AIWatchObj link to the TrolPausePt, the link Data will automatically be set to make the AI wait for 5 seconds and play some idling motions. The TrolPausePt Archetype has the AI→Utility→Watch: Watch link defaults property, and it is from here that the link Data inherits the necessary values.
The values of the property are only read at the moment the link is created, so the response of specific AIs can be changed via the Data of specific links. Similarly, the property cannot be used to modify the Data of links that have already been created. For a change in the property to affect the Data, the link has to be deleted and remade.
Another useful application of this property is to set the Data of AIWatchObj links created during conversations. The mission author would add the property to the destination object, and when the conversation is running and the link is created, the Data will be inherited from the property.