The Yo App Only Allows People to Message Each Other the Word 'Yo'

 - Jun 20, 2014
References: & mashable
A simplistic messaging mobile app that only lets you say 'yo' (aptly named the Yo app) has bested Facebook's Slingshot for iOS. The absurd quality of Yo, where you can only text 'yo' or at most 'yoyo' to your contacts, has clearly attracted a lot of downloads, not to mention angel investors. The free app has received over $1 million in funding and recently cracked Apple's top 150 free apps list. The next day it reached #47 most downloaded in the Apple Store, while Slingshot remains at the #50 spot.

Yo app is only available in US stores, but is downloadable for both iOS and Android. While Slingshot is still beating Yo on Android, the surprise surge from the simplistic messenger is definitely worth taking note of.