One of the first things you learn as a new copywriter is how to use the “4U” technique. There’s some debate about where this neat little copy trick originated, but most point to Michael Masterson, who described it in his Accelerated Program for 6-Figure Copywriting as “the four critical parts that can supercharge any direct mail bullet, any subhead and any headline.”

Sounds pretty good, but what the heck are the Four U’s?

As Masterson describes it, the Four U’s represent the elements you must include to make your headline more powerful:

  • Urgency
  • Usefulness
  • Uniqueness
  • Ultra-specificity

So, for example, here two versions of a direct-response headline, one using the 4U technique and one without:

Without 4U: Increase Your Bottom Line By Installing a Miscrosoft Server
With 4U: Save $12,00+ Per Year With A Microsoft Server That Streamlines Your Business And Lets You Work On The Go

See the difference? The 4U copywriting technique certainly says more and makes you want to keep reading.

But now, years after this Four-U copywriting trick first appeared, there seems to be some debate about it, namely in regard to email subject lines.

Many marketers and copywriting services now say that the 4U technique is also critical to getting more email “opens” from your subject lines. But in our experience, this isn’t always true. In fact, with email subjects, less is (almost always) more.

Let’s take a look at 2 different email subject lines, but for the same email.

Which would you open?

1) Subject: How’s your grammar today?
2) Subject: This week only: Free English course improves your grammar by 300%

Chances are, #1 would get more opens, simply because of the curiosity factory. And to us, that curiosity factor nearly always outweighs the 4U system in subject lines. Now, this doesn’t mean that the curiosity factor works for every type of email. But in our experience, if you can get your email to stand out and look original — without saying too much — more people will open it to see what it’s about.

Of course, another thing to consider here is the conversion rate. Let’s say that only 1% of recipients open email #2. But if 100% of those people actually click and buy, then the 4U version just might be more appropriate after all in this case.

The trick is finding a way to make that subject line intriguing and relevant to the content inside, without giving everything away. (If the messages are too dissimilar, recipients will be surprised by the content of the email and likely ignore it. If the subject is too specific, people will immediately think “Oh, I don’t need that,” and delete the email before every seeing your great sales copy inside.)

If you’re not sure what kinds of subject lines will work best for what you’re offering, the best way to find out is to test, test, test. Run A-B tests on your subject lines, and be sure to look at your conversion rates in addition to your opens.