Newsletter sponsorship consists of buying ad space on an email newsletter.
Newsletter sponsorship is a means to target niche markets and professional audiences. Rates are per issue or periods and based on the number of subscribers.
This media vehicule has some limitations :
opening rates are uncertain
circulation numbers are usually unaudited
An example of newsletter sponsorship on IAB Smartbrief :
The sponsorship ad specs for the newsletter above :
A newsletter with sponsorship skin :
Another background skin newsletter :