Question 1

What is the ideal email subject line length?

Accepted Answer

Research from Litmus and Mailchimp shows that 30-50 characters (6-10 words) typically yields the highest open rates. Under 30 chars looks empty, over 70 chars gets truncated on mobile (where 50%+ of email is now opened).

Question 2

Do ALL CAPS subject lines hurt deliverability?

Accepted Answer

Yes — writing in all caps can trigger spam filters and is widely seen as shouting. SpamAssassin and similar filters add a small score for caps-heavy subjects. Use Title Case or sentence case for best results.

Question 3

Are emojis in subject lines good or bad?

Accepted Answer

Emojis can boost open rates by 10-15% in marketing emails when used sparingly (1 emoji, relevant to the topic), but they render differently on different clients and can look unprofessional in B2B contexts. The tester shows how each emoji displays across Gmail, Outlook and Apple Mail.

Question 4

Why are some words flagged as spam triggers?

Accepted Answer

Words like 'FREE', 'WINNER', 'CASH', 'URGENT', '$$$' are heavily weighted by spam filters (SpamAssassin, Gmail's classifier). A single occurrence is usually fine; stacking many of them significantly increases the spam score. The tester counts and warns about them.