In the past, marketing had one tangible constraint: the cost. at Unica, a provider of enterprise marketing management software. Budget is still a concern, but many marketers are disillusioned by the availability of low-cost channels such as email and Google's YouTube. Alterian, a marketing solutions vendor, recently released a survey of 852 marketers in North America and the UK, 69% of whom use three or more applications to store and analyze their marketing and campaign data in their daily operations; 20% use seven or more. With so many disparate solutions, it's no wonder marketers have difficulty managing excess. There's no sense of "too much" when the campaign is seen as having value. Typically, the customer response to "too much" is to turn off. As one marketer put it that the easiest way to know you're doing too much is often the most painful -- opt-outs and a drop in customer retention.