The majority of digital marketers (74 percent) use general email sign-up forms on websites, according to a new report from ExactTarget. These forms are effective 42 percent of the time. The report was generated from a survey of 395 digital marketers in which respondents identified tactics they use to grow their email lists. The report also revealed that 45 percent of digital marketers are capturing email addresses on Facebook, which has a 31 percent effectiveness rate.