You need to sign every e-mail, experts say. Just write thanks. The logic is straightforward. Thanks does not come across as stiff, or cloying.E-mail scheduling application Boomerang examined 350, 000 threads to see which closings obtained the best response rates, this year. Got a response 62% of the time, compared to a 46% for e-mails that lacked closings that were grateful. Email sign offs are great when you hope to get someone to react to your e-mail or you are requesting information, says an information researcher in Boomerang, Brendan Greenley. These thankful sign offs outperformed closings that were tried and true like best.