Push notifications provide brands with unparalleled opportunities to engage their mobile customers. If you’ve got a popular app like Facebook on your mobile device, you’re likely getting these alert style messages which appear right on your phone’s home screen daily. In fact, fifty-two percent of users who download an app opt in to receive push notifications.

For marketers, push notifications are quickly becoming an essential component of any successful mobile strategy. They create unique opportunities for providing customers with relevant, timely information, increasing loyalty, revenue and engagement by up to four times.

A recent study by Urban Airship, however, has found that some industries are already seeing declines in push notification opt-in rates – some by as much as 20%. They are still an effective way to connect with customers, but they must be done well.

Let’s take a look at five things you should know about push notifications.

They're Uniquely Suited to Drive Results

A few years ago, Google’s VP of commerce shared the astounding stat that the average US consumer is never more than 3 feet away from their phone. That may be a bit of a stretch, but there’s little question we are all extremely attached to our smartphones. In fact, according to the renowned venture capitalist and thought leader Mary Meeker, people check their phones 150 times a day.

Short of broadcasting your notifications directly onto consumers’ eyeballs, there’s no better way to get in front of your customers than via the home screens of their mobile devices. Moreover, consumers opt in to receive push notifications; so brands have an existing relationship with customers and their permission to contact them.

The combination of a prime position on the home screen and the fact that recipients opt in makes push notifications powerful drivers of customer engagement and loyalty. On average, app users who enabled push notifications were found to have an 88% higher engagement rate, with a 3x higher retention rate compared to those who disabled push, according to Localytics.

Forrester Research reported that marketers saw 50% higher open rates on push notifications versus email, as well as click through rates up to twice as high. And based on their study of more than 10 million push notifications, mobile automation company Kahuna found push notifications can attain a 40% click-through rate.

Timing is Everything

It’s not a surprise, given the importance of taking a data-driven approach to online marketing, that timing is a key factor for push notifications. Research has provided guidelines for timing just about every type of online connection with customers - from the best times to post on social media to the optimal times to send emails.

For push notifications, the issue of when the message is delivered is even more critical. For transactional push notifications,  such as flight updates, gate change information and car service arrival, it’s extremely important that the message arrive at the precise moment the user requires it and not a moment too late.

For engagement push notifications, focused on engagement or revenue, the delivery time is equally important, as different mobile users have different schedules and patterns of usage.

In fact, Kahuna has found that messages that arrive at the preferred time of day for each user, compared to messages that are sent out all at once, perform on average 384% better.

And just as important as the right time for mobile push notifications is the wrong time. 50% of Americans (and 90% of 18-29 year-olds) sleep with their phone right next to them. Unlike an email received at an inconvenient hour, a push notification received at an inopportune time can therefore be highly disruptive. And because a smartphone is regarded as such a personal device, an ill-timed message creates a greater sense of breach of trust.

Content is Still King

In 2014, publishers and mobile developers sent more than one trillion push notifications. This means there is no shortage of competition for the prime home screen real estate on your customers’ mobile devices.

To stand out from the crowd and continue to provide valuable information that drives immediate action, marketers have got to deliver push notification messaging that is both highly relevant and compelling. With only 40-65 characters displayed on a mobile device’s home screen, this can be challenging.

When polled by ExactTarget, 80% of US tablet and smartphone users opted in to push notifications found them “somewhat or very useful.” Making sure your content is clear, concise, personalized, and compelling is the best way to make sure your push notification is not among the 20% that consumers perceive as not useful.

Consumers have a limited tolerance for push notifications that don't enough provide value. As a result, some industries are already experiencing a decrease in opt-in rates, according to a report from Urban Airship. The retail industry, for example, saw a 20% decline in average opt-in rates year-over-year in 2014, from 46% in 2013 to 37% in 2014.

It’s All About Segmentation

The intimate nature of push notifications, appearing on the home screen rather than in an inbox or news stream, creates an opportunity for brands to establish more personal, one-on-one relationships with their customers. Segmentation is key to realizing this opportunity and fostering the sense of trust an opt-in creates.

Behavior-based segmentation is especially effective for push notifications.  When segmenting your opted-in users, identify key behaviors a user has exhibited and also behaviors you want to encourage: completing a transaction, registering for special offers or submitting an insurance quote request. Then segment your users according to whether or not they have completed these actions.

Using segmentation effectively not only creates a better user experience and reduces opt-outs, but it also contributes to higher conversions. Localytics found segmentation results in a 54% conversion rate, versus a 15% conversion rate for broadcast messaging - a 260% higher conversion rate.

They’ve Arrived on the Mobile Web

Historically push notifications have been confined to mobile apps. Their capacity for engagement and building relationships with customers have been one great advantage of native apps over the mobile web.

But as of this April, Google has begun enabling push notifications on Android. Mobile web users can now opt in to receive push messaging from websites that support Chrome push notifications.

The potential for greater engagement this creates for the mobile web is huge. Retailers for example rely on the mobile web for 85% of their mobile traffic and 90% of their revenue. Imagine the long-term impact this could have on their business.

And given that ⅔ of consumers do not download any new apps in a given month, it opens up the possibility of engaging with consumers on their home screens even if they don’t download your app.

What's Next for Push Notifications?

Push notifications enable brands to connect with their customers in the right place, at the right time, and with the right information. This ability to deliver highly relevant messaging during customers’ key mobile moments is a powerful driver of mobile engagement and revenue. But there's a fine line between active engagement and perceived harassment.

Apps have a very successful track record of leveraging push notifications for customer engagement and retention. But even in apps, which tend to cater to the most loyal customers, there have been some signs of opt-in rates beginning to fall.

With the expansion of push notifications across channels, will the success of push notifications continue? As long as brands put the customer experience first, push notifications will continue to evolve as a powerful tool for customer engagement.