As more and more executives demand measurable returns on investment, leveraging marketing channels that are both cost-efficient and low-risk are more important than ever. New research conducted by E-consultancy finds that email marketing is the most cost-effective channel for driving customer acquisition, with more than half of marketers claiming it is an effective sales channel, an increase of 7 percent from the same period last year. Affiliate marketing was second, with 46 percent stating it was cost-effective. When used correctly, the low cost tied to these channels does not only effectively drive acquisition, but it can help drive brand awareness. Recently, eHarmony proved this to be true. You can read about how email helped them increase awareness and drive acquisition here.