Record
Corrections
Corrections are published, dated and kept visible. A reference that hides being wrong cannot be checked.
Send corrections to the address on the methodology page.
Gmail enforces authentication, PTR, TLS and a 0.30 percent spam rate
What changed: Correction: this page said Gmail enforces silently and that Google scopes ARC to indirect mail. Both were wrong. Google's guidelines name the failures they return (4.7.0, 4.7.28, 5.7.1, 5.7.26), and the word ARC does not appear on the page at all. Re-read both help paths and counted; the ARC claim was traced to a citation that does not exist.
Why it matters: If this is wrong, Gmail can reject mail with a clear bounce code or quietly file you in spam.
Do next: Open Google Postmaster Tools and look at user-reported spam over 30 days.Full rule →
Klaviyo counts Apple machine opens toward revenue by default
What changed: Correction: all three Klaviyo sources carried placeholder dates and two had the wrong article titles. Re-checked against Klaviyo's help centre and corrected.
Why it matters: This is how email teams lose credibility in board decks.
Do next: Open Klaviyo's account-level attribution settings, not the campaign ones, and look at the conversion window and whether opens count toward…Full rule →
Klaviyo holdout groups need 400,000 profiles
What changed: Correction: the source was cited with the wrong title and a placeholder date. Klaviyo's page is 'Getting started with global holdout groups', last updated 23 Sep 2025. The effective date was corrected to match.
Why it matters: Without holdouts, “email revenue” is often correlation.
Do next: Check your profile count.Full rule →