Fighting off robots… Get creative with emojis in email subject lines to increase open rates! Feel free to spin in your chair while you wait Keep your email subject line short and attention-grabbing. 51% of emails are opened on mobile devices - don’t forget to check the mobile preview for your email! One Mississippi, two Mississippi… Opening the door to unlimited creativity… A mobile-responsive email can increase clicks by 15%. Always check mobile previews before sending out emails.