Reengage dormant users. According to 500.co, roughly 60-75% of email list subscribers are inactive, meaning they haven’t interacted with any emails from the sender in over six months. According to a survey by AdRoll, 90% of marketers consider retargeted ads to be “as good as or better than the gold standard in digital marketing.” Retargeting inactive subscribers with a new offer through paid ads or email can have impressive results.