In a distributed application there is no "backend" that is hidden from the user and can not be copied. So if you write an application such as a social network and publish it via IPNS, people would be able to "clone" it. You would still be in control of the original application, since you would have the private key allowing to publish to the name under which the application code is published.
Honestly, I would not worry about people cloning your app. There is a powerful network effect for things like social networks, so if you find and occupy an unique niche and are not too obnoxious to your users, a clone would not be successful.
By the way: I guess you know about https://akasha.world/ ?