Recently, marketers have been adopting the mantra “more email, more money.”

If you increase the number of emails you send, the thinking goes, you’ll increase the number of customer conversions. Regardless of your success with this tactic, most marketers are ignoring the other side of the equation: more email can mean more problems, if it’s not done right. Report after report has shown that increases in send rates are accompanied by decreases in open rates and click-through rates.

Why does this matter?

You don’t control when your email actually hits a customer’s inbox; your customer’s ISP does.

For years, Gmail, Outlook.com, Yahoo!, and other webmail clients have focused on preventing spam from hitting user inboxes. That tactic has pivoted, in part, to promoting good email and highlighting for users those emails that are most relevant to them. To do that, ISPs are focusing more on email engagement metrics than ever before.

Though none of the major players say exactly what they measure, open rates and click-through rates (in addition to marking an email as important and forwarding an email) are widely accepted to be among the most influential positive engagement metrics. If your numbers dip in these areas, you stand a chance of having your email:

• Delayed

• Denoted as unimportant

• Filtered to a junk/spam folder

• Rejected outright

For the sake of this post, let’s only focus on why you should be worried about delayed deliveries.

You’re not delivering emails in a vacuum

If your customers have opted to receive emails from you, they’ve likely done the same with your competitors. And if your emails are delayed in hitting customer inboxes, you’ll fall behind in the race for your customer’s attention.

Your problems can compound

Delayed delivery might also mean that your emails are delivered after their shelf life expires (think flash sales and one-day-only free shipping offers). This, of course, is more likely if you’re not utilizing open-time personalization and other techniques to make your emails more relevant.

With customers saying that they now expect personalized, relevant and valuable content each time they receive a marketing email, this is a mistake you don’t want to make.

You’re going to have to switch gears

Delayed delivery is now the first sign that something has gone awry with your email marketing efforts. If you’re serious about maintaining your reputation score (basically an aggregate number based on what ISPs and webmail clients think about you), you’ll need to divert attention away from your normal campaigns to focus on re-engagement campaigns, list cleaning and segmentation.

Those projects are time-intensive and require help from other teams, which means you’ll have less time for sending the emails you’ve been using to convert customers.

So what does this all mean?

Simply put, email is now an engagement platform.

Webmail clients are rewarding good content that’s relevant and valuable to a customer. That means marketers who are treating inboxes like clearinghouses of information need to switch gears.

So, before you fire up the creative and start queuing your messages to hit daily, take a few minutes to make sure you’re giving your customers relevant and valuable emails. In this case, a short-term sales bump may spell long-term trouble.

Email marketing image courtesy of Shutterstock.

Nicole Kerr is a senior product manager at Monetate where she oversees the company’s Engage email product. She was previously a product manager at Nokia Location & Commerce (formerly NAVTEQ) where she helped define, develop, launch and support Nokia/NAVTEQ’s location-based mobile ad platform. She also spent time at Yellow Book USA as a New Media Product Manager.