A recent survey from email service provider MailJet indicates that, at least for UK Internet users, it's the personalization that seems to be the most influential attribute when it comes to getting email clicks. That doesn't hold true for every age group however.
Respondents aged 16-29 actually cited design as the most influential in garnering clicks from them on marketing emails. Design dropped consistently among the most important factors as respondents aged.
While it's anyone guess as to why, it is likely a result of older users being less influenced by appearance and more influenced by substance. In fact, 42.9 percent of respondents to the MailJet survey in the 45-59 age group indicated that personalization carried the most influence.
Another interesting finding from the July study was that attributes such as device compatibility and regularity influence clickthroughs far less than many may have previously believed. In fact, just 17 percent of respondents named each as attributes that influence them to click through to the brand or product being marketed.