Being able to mute your device just by flipping it over isn't a new thing. I remember an app that could do that when I had the Storm2. Now, BlackBerry 10 has the option to do so. It is probably something I'd like to see built into BlackBerry 10 but since it isn't it just means that there's room for a developer to fill that void. It is a bit of a novelty thing as you can just as easily tap the screen to mute an incoming call but it's pretty cool to be able to make use of your device's gyroscope to get the same result.
Flip Shush allows you to not only mute an incoming call but it will mute media too. So, if you're playing music you can pause it by just over your BlackBerry facedown. It works when playing videos in the browser too. There is also the option to mute notifications too.
With apps like these, I like to find use cases. With that in mind, I think about the kids in the house and how they play music from their BlackBerry devices or they're watching videos on YouTube. I'll walk in and want to ask a question, they have to reach and find the mute button or pause button. With Flip Shush, they could just flip the phone over. Thinking about other scenarios it could be useful for - meeting. You may not want any distractions during a meeting, so you could just have your BlackBerry laid face down on the table and all your notifications will be silent.
For Flip Shush to function is does need to run as an Active Frame, at least until OS 10.2. It is free to download however the free version only allows you to mute any media played on your device. If you want the notifications and phone function you'll need to buy these through the in-app purchase option within the app. The pro version is $2.99.
Flip Shush is available for the Z10, Q10 and Q5. There is also a PlayBook version for $0.99.
More information / Download Flip Shush for BlackBerry 10
More information / Download Flip Shush for BlackBerry PlayBook