Wrestling with Big, Old Lists

Recently, a client posed this question (I’m paraphrasing): "I have a list of 350,000 email addresses that I collected over the last 5 years. I don’t know how many of them are legitimate. I haven’t used their email addresses for anything before. I want to announce our re-launch and re-engage users. What’s the most cost effective way to get value from these email addresses?"

The first thing I did was verify that all 350,000 email addresses had, at some point, been willingly provided by individual users. The client confirmed that, while it may have been five years ago, all of these people gave an email address willingly. This is essential, but may still not be good enough (see below).

The second thing I focused on was the idea of "cost effective." Most ESP's will charge for every email sent.  Therefore, it’s tempting to find a way to scrub the defunct email addresses prior to sending the message. I’ve heard of people using email validators; but, I haven’t used one myself. 

Quickly, however, I shifted my attention to trying to understand the potential value of this big list. What makes these email addresses precious to the client? Conversely, what’s at stake if we misuse them?

The list is precious because it might contain some highly engaged users who will be eager to know about the re-launched site. The risk is that we could easily alienate a group of likely would-be users by suddenly sending emails when previously we’ve been completely hands off.  From the users' perspectives, it's a stretch to call a one-time sign up from five years ago "permission" to send marketing material.  Lots of unsubscribes or "marked as spam" are likely consequences.

How to proceed? This is what I recommended. I welcome input if anyone else has wrestled with a big, old list.

Look closely at the list:

• Segment! Ideally, segment by time of most recent login.
• Treat new or active contacts differently from older contacts.
• Consider abandoning all non-active contacts from 6-8 months ago or more.

Craft a smart message:

• When re-engaging old contacts, be very upfront with them: acknowledge that you’ve been out of touch; remind them of how they got on your list ("... about a year ago, you signed up for service ...").
• Make it very easy for them to unsubscribe.

Send in smaller bundles, rather than all at once:

• This will reduce the chances of your message being flagged as spam.
• It will also help you figure out whether or not the list as a whole is worth preserving - if most of the addresses are defunct, then it's time to just walk away.

As with all email marketing, I believe the relationship is more important than the individual campaign.  With a list like this, the relationships with individuals are close to non-existent.  To get real value out of the list, I suggest proceeding with caution.