Every designer I have spoken to about designing for the Apple Watch says the same thing: 99% of all possible app features are going to be better on your iPhone than on your wrist. But for apps like Avocado, the social network for romantic partners, the Apple Watch and other wearables represents an exciting new frontier of design. For the first time ever, apps can let people in love feel each other's touch. And the possibilities of that could lead to something profound.

As a service, Avocado allows two people in a relationship to send each other messages, work on shared lists, keep a joint calendar, and quickly send each other photos. These features are what Avocado founder Chris Wetherell refers to as Avocado's vegetables, the boring, commonplace features any couples software should have. Avocado has been working on an Apple Watch app for months now, and will tap into some of these features: for example, the ability to quickly send pre-written messages is uniquely suited for the Apple Watch, Wetherell says.

In fact, the Avocado app icon makes a brief appearance in the official Apple Watch launch video, which suggests that even Cupertino knows that apps specializing in romance or interpersonal interactions are better on a watch than on an iPhone. But why is that?

The key issue is that wearables seem to solve the intimacy problem for apps like Avocado, making two people feel close together when they're really far apart.

For example, in the Avocado app for iPhone, you can send your partner a virtual hug, a feature that seems simple but is actually profound. To send a hug using Avocado, you actually hold your iPhone up to your chest and feel it buzz against you, like a heart beat. It's a surprisingly effective feature, but it only works for the person giving a hug. At best, the person receiving the hug will only feel their iPhone vibrate in their pocket, which is hardly the same thing.

But with a wearable, that all changes. Avocado can take for granted that users of its Apple Watch app will always have their devices snuggled up against their skin. The Apple Watch app doesn't have virtual hugs, but it does have a 'Kiss' feature. Denoted by a heart, an Avocado kiss allows you to send a simple vibration to your partner's wrist with just a tap. It can communicate anything from an expression of affection, to just a reminder that they are being thought of.

That's it for right now, because Apple isn't allowing third-party developers tap into the Watch's accelerometers, the built-in heart rate monitor, or even the Apple Watch's haptic engine. But these early limitations are typical, says Wetherell. Apple also didn't allow developers to tap into the iPhone 5s's Touch ID fingerprint sensor when it launched, but a year later, any app could use Touch ID.

If Apple ever opens up the Apple Watch the same way, the sky's the limit. The Apple Watch can already let you send messages to a partner by sending them a Digital Touch, but Avocado wants to expand that into serendipitous messaging, in which partners can communicate with each other just by making slight gestures that are picked up by the Apple Watch, then sent to each other as vibrations. Avocado also envisions allowing couples to exercise together, by matching up heart rates. In Avocado's hands, it's possible the service could build an experience around it that takes it from curious novelty to something more meaningful.

None of this is here yet but "it feels inevitable," according to Wetherell. "Wearables can't help but improve relationships in an increasingly virtualized world." With the physical gulf between real-world friends and lovers feeling broader than ever in an age of ubiquitous sharing and social media, maybe wearables are the gadgets that finally bring us all back together?

Avocado for Apple Watch will be available for download on April 24, the first day of Apple Watch sales. You will be able to download it here.