Exchange & SSPhttp://www.liveintent.com/
LiveIntent is the only RTB display platform for email and newsletter banners. LiveIntent has a 100% exclusive exchange premium publisher newsletters like The New York Times, Conde Nast, Hearst, AOL, Time Inc., and 100s more. Becuase LiveIntent inventory is targeted when an email newsletter is opened advertisers can buy and optimize just like web display.
Although there is only one page of impressions, advertisers can expect to see 2-5x lift in CTR and site engagements.
Tips for campaign set up:
Accepted ad Sizes: 300x250, 728x90, 300x600, 160x600, 970x250