We’ve been hearing that “daily deal emails are dead” for the past few years, but they never quite seem to disappear. We’ve read about their “troubled” business models and stock valuations, but inboxes around the world continue to receive these plucky deal emails day after day. What’s the real story?

We were curious about the future of Daily Deals, so we did some research. It turns out that time machines are very easy to build, but there’s no guarantee the person you send will return. Going back to the drawing board, we decided to look through our email data. This, of course, was the more difficult approach since we have an abundance of email data.

During the course of our research, we learned interesting things, like using the word “bowling” works better than using the word “game.” For you email nerds out there, we learned that Yahoo may be a popular ISP in the US, but international subscribers prefer to use their Hotmail address. Also, you may not want to use the word “deal” in your email. That was a surprising one. I mean, even if you’re not a daily sender, there might be some tips here for you.

Check out our research: The Truth About Daily Deals where we analyzed 4.4 billion emails from more than 2,000 Daily Deals, and condensed it all into 28 colorful charts.