As an advertiser you can target users based on very specific details, and track any user that responds to your advertisement campaign.

You get all the access (AKA, you know which part of your customer base resulted from targeted ad campaigns, so anything you can target on, you can attribute to that subset).

Regarding elections and digital platforms, a Dutch policy advisory states that the government should disallow non-transparent political advertisements (all advertisements should clearly state who sponsored them and to promote which political cause, if any), and to ensure that political parties can not hide their trade-offs, they shouldn't be able to micro-target people with a different message (increase taxes vs. decrease taxes, depending on what makes the user more likely to vote for you).