E-Marketing Strategy: E-mail Marketing: An Old Workhorse That Still Pulls Its Weight
Start by sending a "Best Of" style e-mail every two weeks. If people on your list complain, try every month. If you have more than one e-newsletter—one to promote discounts and one to promote content—for example, try sending one at the beginning of the month and the other two weeks later.
Gauging An E-mail's –Effectiveness