Hey.

One word. No in-depth meaning. No clues as to what comes next.

"Hey.", as much as it defies all common sense, was one of the most impactful email subject lines ever. (In case you didn't get it, it was an Obama election campaign appeal in 2012.)

Now hey, I'm not suggesting that you use it in every email that you send out. But there is something to be said for incredibly short and direct email introductions. Perhaps it's the contrast, a breath of fresh air surrounded by a sea of verbosity. Perhaps people's interest is simply piqued by such an unusual appeal.

But hey, try it. Or better yet, try a couple variations — A/B testing (which I'll cover more in a future post) lets you pit one or more experiments against one another. Call it survival of the fittest subject lines. Even the experts will admit they can't necessarily predict human behavior, however the data you get back won't lie.

Just be sure to let me know how it works... if you see me on the street, say hey.