Ads within subscriber emails??

I have been approved for AdSense and am about to get it up and running. However, I’m wondering about posts that are automatically emailed to my subscribers. Do those email have ads in them, or can they? And do they count as “impressions” for AdSense?

If you want to encourage your subscribers to view a post on your site, do you send an email with a link to your new post instead of having it within an email? I’m not sure how to go about this.

Thanks!