Forrester Research has released its email marketing vendor report, in which the research company analyzed nine enterprise-class email vendors. Strongview, Epsilon, Oracle Responsys and Salesforce ExactTarget were identified as leaders in the space. Silverpop and Yesmail Interactive were named "strong performers." Acxiom and Experian Marketing Services were named "contenders" and Zeta Interactive was called a "risky bet" in the report.