What actions count as positive signals?
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Not every recipient action carries the same weight. Mailbox providers rank engagement signals from "weak hint" to "strong vote of confidence," and after Apple Mail Privacy Protection broke open tracking in 2021, the ranking matters more than ever.
Strongest positive signals
- Replies. A real human typing a real reply is the closest thing to ground truth that a filter can see. Spam almost never gets replies.
- Move to inbox / "Not spam". The recipient is overruling the filter. Providers learn from that immediately.
- Add sender to contacts. Explicit permission. Nearly impossible to fake.
- Forwarding. Implies the message was worth passing on.
Medium-weight signals
- Clicks. Strong because they require action and intent. Watch for security-gateway bot clicks (Proofpoint, Microsoft Defender) which can inflate the number.
- Long read time. Some providers track how long a message stays open. A four-second open and a forty-second open are not the same signal.
- Star, flag, or label. Recipient organizing your mail = recipient values your mail.
Weak signals (don't lean on them)
- Opens. Apple Mail pre-fetches images, which fires the tracking pixel without a human seeing anything. Open rate inflation can be 30 to 50 percent depending on your audience mix.
What to do with this
Build your reporting around clicks, replies, and unsubscribe rate. Stop optimizing subject lines for open rate alone. If your reply rate is climbing campaign over campaign, your reputation is in better shape than the open number suggests. If you want to see what your sending domain looks like to Gmail and Outlook right now, Review My Emails will show you.
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