Finding sweet spots and tipping points

We email marketers often look for the sweet spots in our email programs — the points in an email cycle when subscribers are most likely to do what we want, like purchasing or signing up for an event.

We can use testing to get answers to questions like these:

• Which acquisition source delivers more qualified subscribers? 
• How many emails should we send in an onboarding sequence to move new subscribers to convert?
• Which combination of subject lines, images and content will get the most conversions?

As helpful as this information is, it shows you only one side of the email picture. You also need to know your tipping points — when your emails are more likely to push subscribers into opting out, spam-complaining or ghosting you. Testing helps here, too, with questions like these:

• How many email campaigns can we send in a week before we start irritating subscribers?
• How much content can go into our emails before Gmail clips them?
• How many new subscribers do we lose because we use double opt-in?
• How many emails are too many in an automated series like onboarding or abandonment?

These can be scary topics because we don’t want to offend our subscribers to the point where they unsubscribe, report our emails as spam or ghost us. So we don’t try to find out. But not knowing the answers means we could leave money on the table out of fear or burn out our list through recklessness.

Simply put, seeking out the sweet spots in our email programs is more palatable than knowing where the tipping points are. But we need to know both so we can balance both courage and caution in our email programs.

Sweet spot versus tipping point

The sweet spot, in my usage, is the point where the way we email our customers and subscribers moves them to take the actions we want. Testing helps us identify those sweet spots, which is why it’s so important to set up and run your tests properly. 

Everybody likes to talk about the sweet spots — the multivariate test that revealed the most fruitful approach to Mother’s Day messaging or the long-tail testing that delivers the most accurate picture of an email campaign’s performance. I’ve written extensively about them, so I don’t intend to go into detail about them here.

But we don’t often talk about the other side of the coin — the tipping points of email. In my usage here, the tipping point happens when our email tactics become counterproductive. Instead of generating positive actions, we tip our subscribers and customers over into negative actions, like unsubscribing, spam-complaining, blocking or ghosting. 

We should talk about these situations, though. Knowing your tipping points will help you understand your customer behavior better and help you see where to draw the lines to avoid angering customers with negative consequences. 

Dig deeper: Email marketing strategy: A marketer’s guide

What are your tipping points?

If you’re a veteran emailer, just thinking about list churn, revenue loss and deliverability issues can make your hair stand on end — and it should! 

The only problem is that we often don’t know for sure whether sending more emails, adding more weight to our messages or revamping our message templates will create tipping points or sweet spots.

Frequency is probably the most common tipping point. But instead of testing to learn how far we can go before we start to annoy our customers, we hesitate, giving way to the old fears that have held us back in the past. 

We might know that sending two emails in an abandoned-cart sequence often gets good results. So what about sending three? If we fear that three emails will drive our customers away, but we don’t test to find out, we’ll just leave it without knowing whether three is the actual tipping point or the sweet spot.

The same can be said for onboarding emails. Sending three to five emails in a coordinated series isn’t unusual, but I’ve seen brands send 10 or 15 emails. Is that too many, too few or just right for your audience? If you don’t test, everything is just a guessing game.

Using testing to find your tipping points

Testing can show where customers stop responding, which emails get more attention and which ones either don’t move the needle or generate negative interactions. However, we usually test to find a nice number and end the test when we think we have achieved the winner.

But testing also can show you when you go too far — either by getting no response or negative responses. Again, this makes most marketers nervous. So, instead of pushing boundaries a little to find the optimum number, we back off with no more insight than before we began testing.

The thing to remember about tipping points is that no one is right in all situations. As with sweet spots, they will vary by brand, audience, product, situation (promotional versus transactional, for example), time on the list and many other factors that make your list different from everyone else’s. 

Testing can show you both the frequency, cadence and series length that is right for your needs — the sweet spot — and the tipping point into negative consequences. It’s all a balancing act. 

Tipping points and ROI

Up to now, I’ve referred to tipping points as the point where an email message can tip subscribers over into negative actions like unsubscribing, spam-complaining and ghosting. These can affect your revenue if they come from paying customers and can affect your sender reputation, deliverability and inbox access.

However, another tipping point to consider is when you no longer earn enough ROI on those extended emails to make them worth doing, whether it’s simply a lack of action or whether negative subscriber actions outweigh any revenue or conversions the emails bring in. You don’t need to see a spike in opt-outs or spam complaints. If the return isn’t there, why risk exposing your email program to potential damage?

This brings to mind the balance I spoke about before. Knowing your tipping point lets you make more informed decisions about email frequency, cadence and numbers. You won’t be guessing or assuming you know what your subscribers and customers are doing. 

3 areas to watch for tipping points

“Too much email” is the main reason customers say they unsubscribe or go inactive on an email list. But finding the right email frequency — and knowing where the tipping point into negative activity occurs — is much more complex than just deciding whether to send one or two email campaigns in a week.

Tipping points happen all through your email program, too and in places where you don’t expect to find them. In this section, I’ll address three areas where testing and tracking email metrics and activity can help you spot and avoid these tipping points.

1. Frequency

When we don’t test for email tolerance, we either send email heedlessly and burn out our lists or we assume “Less is more” without any testing evidence. Both tactics can keep email from realizing its full potential.

Test one segment of your audience and look for insights you can apply to the rest of your list. Consider who might tolerate a higher frequency and who might be too risky. 

But you don’t have to wait for test results to begin to look for ways to maintain regular contact with your list but to reduce the load. Start by looking at all the ways your customers receive your emails. You might find they receive more emails and at different intervals than you realize.

They might get your regular promotional emails, plus transactional emails, triggered messages based on interests, behavior or purchases, announcements from other departments or divisions in your company, customer service queries, win-back or re-engagement emails and other messages that are beyond the marketing team’s control. 

You can set up a contact strategy to manage or limit email sends. For example, you can hold out business-as-usual (BAU) emails from subscribers or customers in onboarding or conversion email sequences. Or, suspend abandoned-browse emails to customers who are in abandoned-cart sequences. 

Check my earlier MarTech article, “Frequency testing: The key to unlocking more email revenue,” for a frequency test that helped a client increase frequency and revenue even though the numbers might have made you think otherwise. 

You can apply these criteria to set up a reactivation program to bring back lapsing, lapsed and dormant customers and to find the tipping point where you no longer see any return.

Dig deeper: 9 steps to make an email reactivation program that really works

2. Email clipping

This is something you can’t blame on your subscribers. Instead, the email server cuts off your email message before the end. This happens most often in Gmail and Outlook, especially if the total file size of your email exceeds 102KB. That’s your tipping point! It includes all text, images, HTML and other components. 

In a clipped email, the footer usually disappears and with it goes the tracking pixel, unsubscribe link (required by laws almost everywhere in the world), message identification required by CAN-SPAM in the United States and even promotional content, like the bottom module of a three-module email, each with an offer. 

Subscribers usually can view the missing content if they click a link on the message, but you can’t assume they’ll take that extra step, especially if they’re on a phone or tablet. And even so, would you prefer them to click to read the whole email or click through to the landing page and action your CTA?

QA testing, either in your ESP or with an outside service like Litmus or Email on Acid, can predict whether your email will get clipped. Use templates with minimal coding and a strong design hierarchy that forces you to be selective about what goes into the email. It puts the most important information (including an unsubscribe link) at the top of the email and limits the number of modules, images and formatted copy blocks. 

Dig deeper: How to produce brand-approved email designs on time and on budget

3. List growth

List acquisition has its own tipping points, especially when reviewing single opt-in (with a non-bouncing confirmation email) and double opt-in. I won’t get into the merits of confirmed versus double opt-in for list acquisition, but I will say that one area that people don’t discuss enough is where the tipping point happens in each process.

We usually use engagement metrics and deliverability to measure whether COI or DOI delivers a better quality of email subscribers — people who open and act on your emails. But to get the true picture, we have to go beyond these metrics to look at conversions. 

Testing and tracking opt-in activity to find the sweet spot (high opt-ins, good delivery, high conversions) and the tipping point (where lower list quality outpaces conversions or revenue). 

It’s widely supposed (and often incorrect) to assume that a single opt-in will create bad deliverability because it doesn’t automatically prevent problem email addresses from getting on the list. But you must study your own list activity to see how it behaves and whether your tipping point overshadows your sweet spots.

Dig deeper: How to send more emails and grow your subscriber list

Final thoughts: Caution and critical thinking, not recklessness

You might think I’m giving email marketers the green light to push subscribers to the brink to learn their breaking points. Nothing could be further from the truth!

Instead of assuming we know what will annoy our subscribers enough to cause them to retaliate, we need to apply critical thinking that incorporates what we know about our customers and the customer journey. 

Our customers and subscribers are constantly sending us signals. We just have to listen to what they tell us, not just what we assume they’ll say.