Very often, we developers struggle to market our app more than to code it.
The Arc is a social platform exists to amend that. The Arc allows developers to help out each other through cross reviews and ratings.
While this will never (and should never) replace user reviews and ratings,
it is particular useful for apps in the earlier stages to get feedback and visibility in their respective app store.
If your app works great but lacks visibility, this is a great place to start.
The Arc - Exclusive App Review Club - free genuine rating and review for your apps from other developers