Seventy-two percent of respondents to a survey conducted by SKYLIST cited deliverability as a persistent problem in a survey of marketing professionals, reports ClickZ. The number-two challenge is analyzing campaign results, which 44 percent of email marketers cited. The survey also identifies how email marketers measure deliverability rates: the number of email messages successfully delivered topped the list at 38 percent, followed by the number of opened messages (27 percent). The survey was conducted by SKYLIST to help develop a newly launched product that monitors deliverability, StormPost 2.4.