Recently the email deliverability community has been abuzz (more than usual, that is) about the value of inactive subscribers, thanks to MailChimp’s detailed analysis of the process of pruning inactives. Since that post, many in the industry have done a great job of expressing a few caveats to the data, including a great writeup by Al Iverson on his SpamResource blog.

That said, I won’t rehash what’s already been posted, but I did want to add an additional caveat I’ve heard discussed but not seen posted publicly. An important footnote to this article is that MailChimp has a set of tools designed to ensure data quality from all of its senders. The opt-in forms they provide to their users are double opt-in, and they use a number of algorithms to ensure that all customers are bringing quality lists into their systems.

Obviously, there’s no inherent issue with these tools – in fact, they are a great example for all senders to follow and many ESPs have similar policies. However, it also means the data used in their study may not necessarily match your own dataset. Even their inactive subscribers have been through a rigorous list quality process and are likely double opt-in. If your own subscriber list meets the same criteria, then you are following best practices and likely will have no problem sending to inactive contacts (within reason). However (and Al alluded to this as well), if portions of your list are compiled through Point-of-sale entry, single opt-in, or your organization’s membership records, you are likely to have a higher risk when sending to inactive subscribers.

MailChimp’s analysis is a great starting point, based on detailed statistical analysis and a huge dataset. But it’s important to remember that there is never a one-size-fits-all solution, and what’s pure gold for one marketer may be scrap metal for another.

– BG