Marketing ROI (Return on Investment) is the resultant financial gain
or loss from marketing and/or promotional activities with which you are involved.
It's important to track it for your marketing campaigns, promotions
and ad spends so that you can maximize your profits.
Tip: A good ROI is the single most important factor in detrmining marketing success.
All of your promotional activities should be tracked so that you can pick the
winners and discard the "waste".