List turnover biggest issue for e-mail marketers

39% of e-mail marketers said list turnover is their biggest challenge in a survey conducted by JupiterResearch. 24% of respondents said they plan to implement a viral marketing campaign, only 10% said such actions were very successful. 15%% of survey respondents plan to begin appending email addresses to their customer lists, but only 4% of those who had tried this tactic rated it successful.