Many marketers mistakenly summarize their entire email in the subject line, removing any incentive to open it. To increase curiosity, provide only a hint or a compelling data point from the email's content. This creates an information gap that subscribers feel compelled to close by clicking.

Contrary to recent best practices, testing shows that starting a newsletter subject line with the edition number (e.g., "[Scoop #42]") can now significantly increase open rates. This highlights the need to constantly re-test old marketing tactics as user behavior evolves.

Contrary to old advice, adding a newsletter edition number to the subject line is now highly effective. Specifically, putting the edition in brackets (e.g., "[Scoop #12]") before the main subject line has been shown in A/B tests to increase open rates by approximately 20% compared to a standard subject line.

A highly effective email tactic is using a compelling statistic as the entire subject line, with no other text or call to action. This piques curiosity by presenting a data-driven statement, leading to an average open rate increase of 19%.

Contrary to old email marketing wisdom, testing fully capitalized subject lines can significantly increase open rates by 3-4 percentage points. Modern spam filters are less likely to penalize this tactic, making it a viable test for grabbing attention in a crowded inbox.

Switching from clear but safe subject lines (e.g., '3 ways to...') to provocative, curiosity-piquing ones dramatically improved open rates. The speaker notes that if a subject line feels slightly uncomfortable to send, it's probably a good sign.

A counterintuitive yet effective email tactic is capitalizing an entire word in the middle of a subject line, not at the start or end. This simple, cost-free A/B test is trending because it breaks visual patterns in the inbox, leading to a reported 16% open rate increase for B2B and 21% for B2C.

Many marketers mistakenly reveal the entire value of an email in the subject line, killing any reason to open it. To maximize opens, provide a compelling hint or create a curiosity gap rather than giving away the full story.

Contrary to previous best practices, adding a newsletter edition number in brackets within the subject line is now highly effective. Recent A/B testing reveals this tactic can increase open rates by approximately 20% compared to using a standard subject line alone.