Almost half of b-to-b marketers (47%) said that improving their email programs relied on increasing their ability to deliver relevant content to specific segments of their audiences, according to a new report from BtoB Magazine. BtoB's "Email Marketing: An Established Channel Evolves," revealed that 43% of b-to-b marketers rely on lead nurturing, 30% rely on list segmentation, 25% rely on increasing personalization and 24% depend on analyzing data. The report also showed that content is a challenge among b-to-b marketers with 58% of respondents facing hurdles in this area. In addition, 40% of those surveyed said that perceived difficulties in measuring ROI was a challenge. Deliverability concerns 34% of marketers and and problems with expanding opt-in lists is an issue for 30% of marketers surveyed.