(Page 7 of 9) See These 9 Terrible Business Ideas That Actually Succeeded and Earned Millions:

The Yo App
An app that lets you send a message containing only the word "YO" is valued at just under $10 million.

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The Yo App
The Yo app was once among the top five apps in the iTunes App Store.
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Page 7 of 9

The Yo app was started by an Israeli group which managed to raise $1.5 million from investors.

As of 2014, the Yo app has over 2.5 million users. It climbed to the top five apps in the iTunes App Store, and garnered interest from many venture capitalists. That same year, the app was hacked and just narrowly avoided catastrophe.

After gathering a lot of negative publicity, the company behind the app has reinvented it.

Now the Yo app is a "content notification clearinghouse", notifying its users of interesting videos, images and articles from a mix of 150 publishers. Each notification is called a "Yo".