Sometimes an advertiser may consider canceling a campaign that is "only" breaking even. While I would suggest ways to optimize the ROI, I would also point out that the value of the "free" branding in getting your message out to enough people to generate that break even response has value.
Tax Prep Entrepreneur and Marketing Specialist Chauncey Hutter goes a step further in Direct Response Guru Dan Kennedy's book, No B.S. Direct Marketing:
Truth be told, I'd be happy spending a dollar and getting a dollar back with a $1.00 to $1.00 ROI. Why? Because I am getting a customer for FREE! Most business owners do not look at their promotions this way. They think the promo didn't make any money so they stop running the campaign. Well, I know my numbers and for every ten customers I get coming through my door (even if I don't make any money on them on the front end), 30% will refer friends or family members... I'll make an average of $750 to $1000 per client from our relationship.