“The presence of any type of punctuation mark increased open rates by 9 percent. Question marks are particularly effective at engaging recipients. In fact, the study found subject lines with question marks have open rates 44 percent greater than those with exclamation points.”
The precious space in your subject line may seem like a bad place to ask a question, but according to Venture Beat, it’s a great way to stir engagement. In fact, punctuation marks of any variety increase open rates by 9% when used in the subject line.