The main two factors of success for an ad campaign is the ability to target a qualified audience and to do so at a low price.

This two factors are more and more difficult to reach with mainstream paid channels (Google Adwords, Facebook Ads...), but some alternative channels - such as newsletter ads - can be very effective.

Placing advertisements in niche newsletters is one of the most direct ways to make contact with high-quality prospects. And depending on the popularity of the newsletter, your campaign can generate a massive ROI.