Email marketing is a hit with shoppers, according to a new report from Forrester Research. Today the average click through rate for an email marketing campaign is about 5 percent. That rate is virtually unchanged from 2003, the researcher acknowledges, but email recipients are web retailers' best customers.

Consumers who buy products advertised in email were found to spend 138 percent more than typical non email readers. Furthermore, more than 50 percent of consumers who open and read email marketing messages are likely to purchase other items on impulse.

"Nearly half of consumers who think email is a great way to find out about new products or promotions are willing to pay a premium for products that save them time and hassles," says Forrester analyst, Shar VanBoskirk, in the report, titled, "E-Mail Marketing Comes of Age."

It also finds that three in five customers who forward email ads to friends are women. In addition, younger shoppers between the ages of 18 and 34 represent one third of all consumers who maintain a discrete email address for promotions. "Email has reached almost universal penetration," the report concludes, noting that 97 percent of consumers and 94 percent of marketers use this vehicle.