[throwgraway]

former email marketing automation company employee here: These lists have been sold multiple times before, there may be more "functional" mailboxes or distribution lists (like sales@, it@) than real people, they may be in a dire need of list hygiene, they may contain spam traps, and for the most important part - there is no consent given from the email owners to you. All unsolicited email will end up in spam or trash just because of lack of consent. And if you feed this lists to most of the email automation software then you are cruising for a bruising as they can terminate your account based on that.

[solarisos]

This is a really helpful breakdown, thanks for sharing it. The point about lists being resold multiple times and accumulating spam traps resonates a lot, especially combined with lack of consent. That seems to explain why even technically “valid” addresses still perform poorly. Out of curiosity, in your experience, did any approaches work better than others (for example strict segmentation, very small batch sends, or avoiding purchased lists entirely)?

[throwgraway]

From my former employee and my current experience with email lists:

- Avoid purchased lists at all costs - Apply double opt-in to confirm someone really wants to hear from you (most of the email software supports this out of the box) - maintain a healthy list (no duplicates, dead domains etc) - do not let your list to be covered by dust (for example: if you collected an email and consent from someone a year ago, and there were no sends to this person since, consider removing it from the list). - Spread sends in time - bigger email providers have special requirements for mass mailing, and you will have your sending domain reputation busted if you would not comply.

Additionally, treat the "opens and clicks" statistics with a grain of salt as they are basically unreliable these days - Apple Mail will read that email before the recipient does, Microsoft outlook will click all the links on the message to check for malicious content, some email clients will not fetch images from the message (hence no image responsible for click would be recorded).