I'll speak to that. My understanding is that Facebook has started that process in an experimental manner in Canada to identify the sources of ads that are targeted in Canada. Yes, I agree with that. It's also worth noting that those kinds of procedures would pretty much have to be in compliance with GDPR if this is done, and it is done in Europe. That's an important note.
I'll just add one other thing concerning the social implications of the lack of transparency. That creates, of course, an incentive for candidates to say one thing to one group of voters and another thing to another group of voters, because it is not transparent. That has also been shown to contribute to the phenomenon called the filter bubble, in which there is no common discourse across a political system about solutions to public problems.