What it does NOT mean is that the ISP is randomly deleting your subscribers!
ISPs maintain what are called “feedback loops” (FBLs) for bulk email service providers (ESPs) like FeedBlitz. Reputable ESPs join an ISP’s FBL in order to trap complaints, which in turn means that an ESP can keep its reputation up and deliverability rates high by keeping abuse and complaints down in the long run.
Here’s how an FBL works:
- The subscriber receives an email they don’t want, and hit the “spam” button in their ISP-provided email software.
- The ISP sends the ESP (that’s us) the complaint via the FBL.
- FeedBlitz unsubscribes the recipient automatically.
- We send you the “08: ISP requested removal” unsubscribe reason. We also count this as a complaint against you for use in our metrics and anti-abuse analyses.
Now, sometimes the subscriber will say “but I didn’t do that” – and that may in fact be true. Here’s how errors can creep in:
- They meant to mark a different email as spam but had yours still selected in their email, so you got the complaint in error.
- They forwarded the email to someone else using their email’s forward feature.
- The recipient of the forward is the one who then hit the “spam” button.
- In this case it looks like the original recipient complained because the information used by the ISP in the FBL comes from the original email which contains the original subscriber’s data.
- The original recipient should use the “email to a friend” link instead to avoid this problem.
The recipient can resubscribe at any time using the subscriptions tab.