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5 Things to Know When Developing an App for Millennials

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are a developer's most important demographic, with 85 percent of 18-to-24-year olds owning a and spending an average of 37 hours and six minutes a month on apps. They've grown up accustomed to instant and constant connectivity, in every aspect of their lives from media to shopping to education.

As I've seen firsthand, capturing, and maintaining, their usership is a huge challenge, but a crucial one in building a successful app. Let me share what I've learned in developing and refining StudyBlue, a crowdsourced learning app used by 8 million millennials. Most of them str college-aged and grew up with texting and Snapchatting as second nature. When seemingly every problem can be solved by , the heightened expectations of these digital natives make them the most fickle fans and vocal critics.

1. Smartphones are the rage but true mobility is cross-platform.

Take the meaning of "mobile" literally. It's more than functionality on smartphones. For an app to be truly mobile, it has to work full force across all platforms, in all contexts of the user's daily life. Most of our users take notes on their laptops, with larger screens and keyboards more conducive for typing and adding content. For reviewing flashcards in between the classes and activities, they turn to their phones.

What's important to them is the ability to access their study materials on the walk to class, open their laptops when they reach the lecture hall and switch seamlessly to the same materials on their laptops. Millennials are comfortable in front of any screen. Their apps should offer cross-device flexibility to accommodate that.

Related: Millennials Check Their Phones 43 Times a Day. This Is What They're Looking For. (Infographic)

2. Streamline old habits, don't try to force new ones.

The most popular apps succeed because they take advantage of technology to assist users in something they're already doing. People were calling for a car service and asking for restaurant recommendations before and , but the convenience they offer made them instantly adoptable without much adjustment on the user's part.

With StudyBlue, we didn't set out to reinvent learning -- we set out to enhance the learning experience by making it easier to create, review and share study materials. Our most popular features are ones that incorporate familiar tools and habits in new ways. Having grown up with auto complete and news feed suggestions, our users expect sites to get smarter the more they use them. We applied these functions to our content library, which recommends content based on topics the user is currently reviewing.

3. Transparency and empathy can make fans of critics.

Millennials are a vocal audience accustomed to instant responses, especially on , so it's especially important to communicate with your users, empathize with their frustrations and admit to mistakes. They need to know there's also a human on the other side of their screens.

When our app experienced an outage during finals season last year, we engaged with users on for eight straight hours. While we were tempted to throw all our focus into fixing the app, we knew it was even more important to let anxious college students know what was going on. In response, we received messages of support and encouragement telling us to "hang in there" and celebrations when we fixed the bug.

Related: Build Great Customer Service Into Your Business With These 5 Tips

4. These are people, not a demographic.

Don't make assumptions about your users' preferences based on what you think you know about them. Conventional wisdom -- and studies -- tell us millennials are constantly plugged in, whether it's via text, Facebook messenger or . The initial version of our product mimicked that same connectivity for studying through real-time collaboration features like study groups and class forums. We also offered more "passive" features, like asynchronous note sharing and messaging.

Surprisingly, it was the asynchronous passive collaboration tools that were most successful. We realized that at the collegiate level, especially in large lecture halls, students often don't know their classmates and are hesitant to actively reach out to them. Our users aren't just students, but also dorm residents, new graduates, athletes, part-time workers with busy schedules and/or young people who are too shy to approach their classmates.

Data doesn't predict everything. To create an intensely personalized tool users love and keep using, we must always take into consideration their multiple identities and contexts.

5. Be cutting edge, not bleeding edge.

It is a drastically different experience being an 18-year-old in 2015 than it was in just 2010, before Instagram, Snapchat or Venmo. Achieving a balance here might require returning to abandoned ideas for new insight. Even in five short years, features that may have been too bleeding edge, like real-time study groups, are now starting to show potential.

In the face of this audience's continually shifting preferences and behaviors, the best advice I have is to envision your company and product as a platform early on: something that can change, adjust and expand. Something with a broad objective, and not a singular purpose. This will give you flexibility to make UI and UX decisions as millennial user trends fluctuate, letting you evolve with them, making your product as useful as possible for as long as possible.

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