I still don't fully understand, what can people do with this kind of data at scale, esp. for politics. Can anyone share some concrete examples? Sure, maybe data

I still don't fully understand, what can people do with this kind of data at scale, esp. for politics. Can anyone share some concrete examples? Sure, maybe data can tell that I'm pregnant, so I will start seeing baby products, but how does it help getting some political outcome (e.g make someone elected)?