How do “move to inbox” or “reply” actions improve reputation?
Still have a question, spotted an error, or have a better explanation or a source we should cite?
These two are the highest-weighted positive signals a recipient can produce. Both because they require deliberate effort and because they're nearly impossible to fake at scale.
"Move to inbox" / "Not spam"
When a recipient pulls your message out of the spam folder, they're directly contradicting the filter's last decision. Providers treat that as a strong correction. A handful of "not spam" actions across many recipients trains the model that this sender, or this content pattern, was misjudged. Filtering loosens for that sender going forward.
The catch: most ESPs don't expose this metric. Gmail doesn't tell you how many people rescued you from spam. You usually only see it indirectly through inbox placement testing tools.
Replies
Replies are the closest thing to ground truth a filter can see. Real conversation. Spam almost never produces real replies, so when a sending domain has a measurable reply rate, providers weigh it heavily.
This is why transactional senders and one-to-one sales senders often have unfairly good deliverability. Their reply rates are naturally high. Marketing senders blasting one-way newsletters can borrow some of this benefit by writing emails people actually want to respond to (asking a question, inviting a reply, signing from a real person at a real address).
How much do they actually move the needle?
Hard to put a single number on it because providers don't publish weights. But anecdotally: a sender with a 1 to 2 percent reply rate and any meaningful "move to inbox" volume tends to keep solid placement even with mediocre opens. The reverse isn't true. High opens with zero replies don't carry the same weight.
If your "move to inbox" rate is low
The diagnosis is rarely "the recipient didn't try hard enough." It's usually that authentication is broken or the content / list is in trouble before the recipient ever sees the spam folder. Review My Emails will tell you whether DMARC, SPF, and DKIM are actually passing for your sending domain, which is where most "low rescue rate" problems start.
Contributors
Who worked on this answer
Every name links to their profile. Every company links to their site. Real people, real accountability.
