The idea came from affiliate networks sending out offers and constantly running into roadblocks of ESP's (Email Service Providers) blocking their accounts for too many offers being sent out. Most of the time offers were getting mailed and deleted or never reached the inbox. Inbox delivery was poor to say the least. This was their major pain.
Our publishers who were constantly mailing newsletters with good content were consistently looking to reduce costs in mailing. Isn't reducing operating cost on everyone's mind? These mailers would receive high activity within their emails and greater inbox delivery which resulted in higher opens and higher click throughs.