According to a survey published in Target Marketing (3/09, p. 37), it’s not online advertising, podcasts, search engine optimization, or webcasts.
E-mail marketing was cited by 28% of the marketing professionals ls urveyed as delivering the strongest ROI for customer acquisition online.
Search engine optimization came in a distant second at 7%.
Given that something like 80% of online purchases begin with an online search, I find this result surprising — and a bit suspicious, to say the least.
BTW, e-mail was also voted #1 for customer retention online, at 39%. This I find more credible: there is no better way of communicating with existing customers than e-mail.