The developers of the "Yo" app must have taken to the above quote from Richard Branson take heart. Because it's one incredibly simple app.

By now you've probably heard of the popular app from Life Before Us LLC. It originated after Moshe Hogeg, CEO of Tel Aviv company Mobli, asked Or Arbel for an easier way to communicate with his wife and assistant. Instead of emails or text messages, Hogeg wanted something simple. Really simple. He envisioned an app that featured large buttons that would send a one-word notification to the recipient. That one-word turned out to be "Yo."

When Yo was released on April Fool's Day Apple initially rejected the app because it "lacked substance." Yo was finally approved and after one month 20,000 people in Tel Aviv had downloaded Yo. The app also went on to raise $1.2 million from investors and swept the world, thanks in part, no doubt, to endless media attention.

While there have been some ups and downs since the app skyrocketed to stardom - it was hacked by college students in June--the seemingly overnight success of Yo has been remarkable. But, as Robert Scoble described it, how did "the stupidest, most addictive app," become such a phenomenon? Here are the five reasons Yo went viral.

1. Provides Value

Yo may sound, well, just dumb and pointless. But it does have value for users. It's just a way to send someone a notification without requiring a response. In fact, the notification can be dismissed. For people who just need to send out a quick message, no matter the situation, without getting trapped into a conversation, Yo is a very valuable app.

2. Easy to Join and Share

Do any of us really enjoy constantly signing in and out of an account? Nope. That's why most of the time youcan login simply login to an app by using your Facebook, Twitter or Google accounts. But Yo doesn't even require that. You can use the app without sharing your email or social media accounts. As the description states, "It's just that simple. Yo."

3. Familiarity

Remember when Flappy Birds was all the rage? You suddenly saw a lot of apps that were essentially copycats of Flappy Birds--Wired reported that 95 of the 300 new apps on iTunes during one week in March were Flappy Birds riffs. Why? Because the app was familiar. For Yo, the app has the advantage of using a popular and common greeting that we've all used or heard at some point:What'sthe most popular line from Rocky?

4. Incentives for Joining

Most apps that go viral offer some sort of incentive for users to join--gift cards, discounts, free upgrades, sense of urgency, etc. Yo, believe it or not, also offers some users a reason for downloading the app. Users in Israel can receive notifications of rocket strikes, and World Cup fans were notified when a team scored a goal. Those are important reasons for those users to jump on board of the Yo bandwagon.

5. Let Other's Promote the App

Marketing expert John Rampton says "When you want an app to go viral, one of the best tactics is to let others promote it for you. That's why developers will send their app out to trendsetters or industry leaders, like bloggers or journalists, for testing or review prior to launch. Once the word gets out, people will give the app a try just to see what the buzz is all about. With so much attention on how simple and/or dum Yo is, that was enough to entice users to download the app to see for themselves."

But, what if you aren't lucky enough to get that juicy million dollar investment? You can still make money off your app by doing the following:

If you develop a simple app that provides value and incentives for your audience, it should connect with them. Remember to make it easy to join, easy for users to share,and that you spread the word as much as possible to make your app go viral.