Open and Click Tracking Are Hurting Your Deliverability - and Opens Barely Mean Anything Anymore

Almost every cold email and marketing platform turns open and click tracking on by default, and most teams never look at the setting again. Two things have changed underneath that default: the open number stopped measuring what people think it measures, and the machinery that produces it - a hidden image and rewritten links - is exactly what spam filters look at.

Why open rates stopped being a real signal

Apple Mail Privacy Protection, introduced with iOS 15, downloads remote images in the background through Apple's proxy whether or not the person ever opens the email. Every Apple Mail user with the feature on registers as an "open" the moment the message arrives. Gmail also fetches images through its own proxy and caches them. The result is that open rate is inflated by an unknown amount that differs from list to list, depending on how many of your recipients use Apple Mail.

That matters for two reasons. First, you can't use a 60% open rate to conclude your emails are landing in the inbox - a message sitting in spam can still show as opened by an automated fetch. Second, any test you run on subject lines against open rate is measuring noise mixed with signal.

What tracking does to placement

• The tracking pixel is a remote image in a message that might otherwise be plain text - a message with no other visible content and one hidden image is a pattern filters have seen a lot of
• Click tracking rewrites every link to point at a redirect domain instead of your own - the visible URL and the real destination no longer match, which is a classic phishing shape
• If the tracking domain is shared with other customers of your platform, its reputation is shared too - one noisy neighbor can put a listing on a domain you never controlled
• Redirect domains are themselves checked against domain blocklists such as Spamhaus DBL and SURBL, so a listed tracking domain drags down every message that contains it

What to do about it

• For cold outreach, turn open tracking off. Reply rate and booked meetings are the metrics that survive; opens don't
• Turn click tracking off too, unless a specific campaign genuinely needs it - a plain link to your real site is the lowest-risk option
• If you do need click tracking, use a custom tracking domain on a CNAME to your platform, on a subdomain of a domain you own, so its reputation is yours alone
• Keep that tracking domain in your monitoring: check it against blacklists the same way you check sending domains, and make sure it has valid HTTPS
• Use the same registrable domain (or a clearly related one) for links and for the From address, so what people see is consistent

For newsletters and marketing sends to consenting subscribers, click data is still useful and the risk is much lower - the recipients expect the mail, so complaint rates stay small. The trade-off is sharpest in cold outreach, where every extra signal counts against a sender with no history.

Check a tracking domain or sending IP against the major blacklists

See how a plain version of your message actually places across seed mailboxes

If a metric can be produced by a robot fetching an image, it can't tell you a human read your email. Measure replies.