To build a list of communications preferences updates you can
- Add a new activity list
- Filter the list for Activity type equals 'Communication Preference Confirmation'
- If you only want updates made by the constituent themselves add a filter for Entered by equals 'Self Service'
This is an example
To find people who have not updated their preferences - you can
- Tag everyone on the list you have just created above - see this
- Then create a list of constituents who do not have that tag