What makes e-mail marketing unique is the ability to both broadcast and target individual personalized content at the same time. It’s also relatively inexpensive compared with other media.
Look at the activity of individual recipients on your list over the last six or 12 months, and people that are fundamentally inactive—who haven’t clicked, haven’t opened, haven’t purchased—take ’em off your list.
What you really need to be concerned about is total respondents and total conversion rates, not how big your list is.
Keep the list extremely private and deal with the purposes people opted in for. That alone will pretty much keep you in the green zone for good e-mail marketing.
