Try this out. Look at the above subject lines.

Just by reading the subject lines and NOT opening the email we do know —

1. If we stop by a Verizon store the new BlackBerry Z10 will be there
2. If we need a new Apple product we can save on shipping at Staples
3. It’s a good time to go to The Gap, we can save over 40%
4. If we want to hear Broadway Stars singing this weekend we can go to the Irvington Town Hall.

Therefore, we can easily say this: Unopened email can bring in orders. People will just show up at the Gap knowing they can save over 40%, or show up at the Irvington Town Hall and see Broadway Stars singing.

Does this tell us that the subject line is not only important for getting people to click-through, but also effective in doing a quick shout out? My answer is yes and no.

Look at which sectors it works well for, namely retail and entertainment. You can use the subject line as a marquee that basically states the offer. But if we look at this Adobe subject line — “Avoid the five pitfalls of personalization” — it’s a little different. Here, I can’t really do anything unless I open the email and read what the pitfalls are.

Conclusion: A subject line can stand in for an unopened email in certain sectors and with certain offers — but not if we have more of a story to tell.