Segment E-mail Offers by Likelihood to Purchase
Customers that previously have bought via the e-mail channel are four times more likely to buy from e-mail again than buyers who've never purchased via e-mail. With that data in mind, it doesn't make sense to use the same e-mail offer for every customer.
Since customers that have bought via e-mail previously are more likely to do so again, e-mail them with conditional offers, such as a 10 percent discount or free shipping only on purchases greater than $100. For customers who haven't yet purchased via e-mail, remove the condition.