The ads that are in your email, they are what we call email marketing. It's already popular and most of the people that are annoyed with this marketing is calling it as a scam. But I've been with that job before and I can say if you are targeting certain people who wants to avail your product will eventually get a good sales.
An e-mail announcement can be very effective. Just do not need to immediately offer people your product. Offer them something for a gift: a book, a consultation, important information, training.
Suggest to visit your site, and only then let's advertise